by Cass R. Sunstein & Adrian Vermeule
Harvard Law School / University of Chicago Law School: Law & Economics Research Paper Series; Paper No. 387 http://ssrn.com/abstract=1084585
January 15, 2008
Conspiracy theories are by no means a strictly domestic phenomenon; they can
easily be found all over the world. Among sober-minded Canadians, a September 2006
poll found that 22 percent believe that “the attacks on the United States on September 11,
2001 had nothing to do with Osama Bin Laden and were actually a plot by influential
Americans.”5 In a poll conducted in seven Muslim countries, 78 percent of respondents
said that they do not believe the 9/11 attacks were carried out by Arabs.6 The most
popular account, in these countries, is that 9/11 was the work of the U.S. or Israeli
What causes such theories to arise and spread? Are they important and perhaps
even threatening, or merely trivial and even amusing? What can and should government
do about them? We aim here to sketch some psychological and social mechanisms that
produce, sustain, and spread these theories; to show that some of them are quite important
and should be taken seriously; and to offer suggestions for governmental responses, both
as a matter of policy and as a matter of law.
The academic literature on conspiracy theories is thin, and most of it falls into one
of two classes: (1) work by analytic philosophers, especially in epistemology and the
philosophy of science, that asks what counts as a “conspiracy theory” and whether such
theories are methodologically suspect;8 (2) a smattering of work in sociology and
Freudian psychology on the causes of conspiracy theorizing.9 Both approaches have
proved illuminating, but neither is entirely adequate, the former because the conceptual
questions are both less tractable and less interesting than the social and institutional ones,
the latter because it neglects newer work in social psychology and behavioral economics,
both of which shed light on the causes of conspiracy theorizing. Rather than engaging
with the conceptual debates, we will proceed in an eclectic fashion and mostly from the
ground up, hewing close to real examples and the policy problems they pose.
Our main though far from exclusive focus – our running example – involves
conspiracy theories relating to terrorism, especially theories that arise from and post-date
the 9/11 attacks. These theories exist within the United States and, even more virulently,
in foreign countries, especially Muslim countries. The existence of both domestic and
foreign conspiracy theories, we suggest, is no trivial matter, posing real risks to the
government’s antiterrorism policies, whatever the latter may be. Terrorism-related
theories are thus a crucial testing ground for the significance, causes, and policy
implications of widespread conspiracy theorizing. As we shall see, an understanding of
conspiracy theories has broad implications for the spread of information and beliefs;
many erroneous judgments are a product of the same forces that produce conspiracy
theories, and if we are able to see how to counteract such theories, we will have some
clues about how to correct widespread errors more generally.
Part I explores some definitional issues and lays out some of the mechanisms that
produce conspiracy theories and theorists. We begin by discussing different
understandings of the nature of conspiracy theories and different accounts of the kinds of
errors made by those who hold them. Our primary claim is that conspiracy theories
typically stem not from irrationality or mental illness of any kind but from a “crippled
epistemology,” in the form of a sharply limited number of (relevant) informational
sources. Those who hold conspiracy theories do so because of what they read and hear. In
that sense, acceptance of such theories is not irrational from the standpoint of those who
adhere to them. There is a close connection, we suggest, between our claim on this count
and the empirical association between terrorist behavior and an absence of civil rights
and civil liberties.10 When civil rights and civil liberties are absent, people lack multiple
information sources, and they are more likely to accept conspiracy theories.
Part II discusses government responses and legal issues, in light of the discussion
in Part I. We address several dilemmas of governmental response to conspiracy theories,
such as the question whether it is better to rebut such theories, at the risk of legitimating
them, or to ignore them, at the risk of leaving them unrebutted. Conspiracy theories turn
out to be especially hard to undermine or dislodge; they have a self-sealing quality,
rendering them particularly immune to challenge. We suggest several policy responses
that can dampen the supply of conspiracy theorizing, in part by introducing diverse
viewpoints and new factual assumptions into the hard-core groups that produce such
theories. Our principal claim here involves the potential value of cognitive infiltration of
extremist groups, designed to introduce informational diversity into such groups and to
expose indefensible conspiracy theories as such.
A. Definitional Notes
There has been much discussion of what, exactly, counts as a conspiracy theory,
and about what, if anything, is wrong with those who hold one.11 Of course it would be
valuable to specify necessary and sufficient conditions for such theories, in a way that
would make it possible to make relevant distinctions. We bracket the most difficult
questions here and suggest more intuitively that a conspiracy theory can generally be
counted as such if it is an effort to explain some event or practice by reference to the
machinations of powerful people, who have also managed to conceal their role. This
account seems to capture the essence of the most prominent and influential conspiracy
Consider, for example, the view that the Central Intelligence Agency was
responsible for the assassination of President John F. Kennedy; that doctors deliberately
manufactured the AIDS virus; that the 1996 crash of TWA flight 800 was caused by a
U.S. military missile; that the theory of global warming is a deliberate fraud; that the
Trilateral Commission is responsible for important movements of the international
economy; that Martin Luther King, Jr., was killed by federal agents; that the plane crash
that killed Democrat Paul Wellstone was engineered by Republican politicians; that the
moon landing was staged and never actually occurred.12
Of course some conspiracy theories, under our definition, have turned out to be
true. The Watergate hotel room used by Democratic National Committee was, in fact,
bugged by Republican officials, operating at the behest of the White House.
In the 1950s, the Central Intelligence Agency did, in fact, administer LSD and related drugs under Project MKULTRA, in an effort to investigate the possibility of “mind control.”
Operation Northwoods, a rumored plan by the Department of Defense to simulate acts of
terrorism and to blame them on Cuba, really was proposed by high-level officials (though
the plan never went into effect).13 In 1947, space aliens did, in fact, land in Roswell, New
Mexico, and the government covered it all up. (Well, maybe not.)
Our focus throughout is on false conspiracy theories, not true ones. Our ultimate goal is to explore how public
14 See Edward Glaeser, The Political Economy of Hatred, 120 Q. J. ECON. 45 (2005).
officials might undermine such theories, and as a general rule, true accounts should not
Within the set of false conspiracy theories, we also limit our focus to potentially
harmful theories. Not all false conspiracy theories are harmful; consider the false
conspiracy theory, held by many of the younger members of our society, that a secret
group of elves, working in a remote location under the leadership of the mysterious
“Santa Claus,” make and distribute presents on Christmas Eve. This theory is false, but is
itself instilled through a widespread conspiracy of the powerful – parents – who conceal
their role in the whole affair. (Consider too the Easter Bunny and the Tooth Fairy.) It is
an open question whether most conspiracy theories are equally benign; we will suggest
that some are not benign at all.
Under this account, conspiracy theories are a subset of the large category of false
beliefs, and also of the somewhat smaller category of beliefs that are both false and
harmful. Consider, for example, the beliefs that prolonged exposure to sunlight is actually
healthy and that climate change is neither occurring nor likely to occur. These beliefs are
(in our view) both false and dangerous, but as stated, they do not depend on, or posit, any
kind of conspiracy theory. We shall see that the mechanisms that account for conspiracy
theories overlap with those that account for false and dangerous beliefs of all sorts,
including those that fuel anger and hatred.14 But as we shall also see, conspiracy theories
have some distinctive features, above all because of their self-sealing quality; the very
arguments that give rise to them, and account for their plausibility, make it more difficult
for outsiders to rebut or even to question them.
Conspiracy theories generally attribute extraordinary powers to certain agents – to
plan, to control others, to maintain secrets, and so forth. Those who believe that those
agents have such powers are especially unlikely to give respectful attention to debunkers,
who may, after all, be agents or dupes of those who are responsible for the conspiracy in
the first instance. It is comparatively easier for government to dispel false and dangerous
beliefs that rest, not on a self-sealing conspiracy theory, but on simple misinformation or
on a fragile social consensus. The simplest governmental technique for dispelling false
(and also harmful) beliefs – providing credible public information – does not work, in
any straightforward way, for conspiracy theories. This extra resistance to correction
through simple techniques is what makes conspiracy theories distinctively worrisome.
A further question about conspiracy theories – whether true or false, harmful or
benign – is whether they are justified. Justification and truth are different issues; a true
belief may be unjustified, and a justified belief may be untrue. I may believe, correctly,
that there are fires within the earth’s core, but if I believe that because the god Vulcan
revealed it to me in a dream, my belief is unwarranted. Conversely, the false belief in
Santa Claus is justified, because children generally have good reason to believe what
their parents tell them and follow a sensible heuristic (“if my parents say it, it is probably
true”); when children realize that Santa is the product of a widespread conspiracy among
parents, they have a justified and true belief that a conspiracy has been at work.
Are conspiracy theories generally unjustified? Under what conditions? Here
there are competing accounts and many controversies, in epistemology and analytic
philosophy. We take no final stand on the most difficult questions here, in part because
the relevant accounts need not be seen as mutually exclusive; each accounts for part of
the terrain. However, a brief review of the possible accounts will be useful for our later
Karl Popper famously argued that conspiracy theories overlook the pervasive
unintended consequences of political and social action; they assume that all consequences
must have been intended by someone.15 The basic idea is that many social effects,
including large movements in the economy, occur as a result of the acts and omissions of
many people, none of whom intended to cause those effects.
The Great Depression of the 1930s was not self-consciously engineered by anyone; increases in the unemployment or inflation rate, or in the price of gasoline, may reflect market pressures rather than intentional action.
Nonetheless, there is a pervasive human tendency to think that effects are caused by intentional action, especially by those who stand to benefit (the “cui bono?” maxim), and for this reason conspiracy theories have considerable but unwarranted appeal.16 On one reading of Popper’s account, those who accept conspiracy theories are following a sensible heuristic, to the effect that consequences are intended; that heuristic often works well but it also produces systematic errors, especially in the context of outcomes that are a product of social interactions among numerous people.
Popper captures an important feature of some conspiracy theories. Their appeal lies in the attribution of otherwise inexplicable events to intentional action, and to an unwillingness to accept the possibility that significant adverse consequences may be a product of invisible hand mechanisms (such as market forces or evolutionary pressures) or of simple chance,17 rather than of anyone’s plans.18 A conspiracy theory posits that a social outcome evidences an underlying intentional order, overlooking the possibility that the outcome arises from either spontaneous order or random forces. Popper is picking up on a still more general fact about human psychology, which is that most people do not like to believe that significant events were caused by bad (or good) luck, and much prefer simpler causal stories.19 Note, however, that the domain of Popper’s explanation is quite limited.
Many conspiracy theories, including those involving political assassinations and
the attacks of 9/11, point to events that are indeed the result of intentional action, and the
conspiracy theorists go wrong not by positing intentional actors, but by misidentifying
A broader point is that conspiracy theories overestimate the competence and
discretion of officials and bureaucracies, who are assumed to be able to make and carry
out sophisticated secret plans, despite abundant evidence that in open societies
government action does not usually remain secret for very long.20 Recall that a distinctive
feature of conspiracy theories is that they attribute immense power to the agents of the
conspiracy; the attribution is usually implausible but also makes the theories especially
vulnerable to challenge. Consider all the work that must be done to hide and to cover up
the government’s role in producing a terrorist attack on its own territory, or in arranging
to kill political opponents. In a closed society, secrets are not difficult to keep, and
distrust of official accounts makes a great deal of sense. In such societies, conspiracy
theories are both more likely to be true and harder to show to be false in light of available
But when the press is free, and when checks and balances are in force,
government cannot easily keep its conspiracies hidden for long. These points do not mean
that it is logically impossible, even in free societies, that conspiracy theories are true. But
it does mean that institutional checks make it unlikely, in such societies, that powerful
groups can keep dark secrets for extended periods, at least if those secrets involve
important events with major social salience.
An especially useful account suggests that what makes (unjustified) conspiracy
theories unjustified is that those who accept them must also accept a kind of spreading
distrust of all knowledge-producing institutions, in a way that makes it difficult to believe
anything at all.22
To think, for example, that U.S. government officials destroyed the World Trade Center and then covered their tracks requires an ever-widening conspiracy theory, in which the 9/11 Commission, congressional leaders, the FBI, and the media were either participants in or dupes of the conspiracy.
But anyone who believed that would undercut the grounds for many of their other beliefs, which are warranted only by trust in the knowledge-producing institutions created by government and society.
How many other things must not be believed, if we are not to believe something accepted by
so many diverse actors? There may not be a logical contradiction here, but conspiracy
theorists might well have to question a number of propositions that they seem willing to
take for granted. As Robert Anton Wilson notes of the conspiracy theories advanced by
Holocaust deniers, “a conspiracy that can deceive us about 6,000,000 deaths can deceive
us about anything, and [then] it takes a great leap of faith for Holocaust Revisionists to
believe World War II happened at all, or that Franklin Roosevelt did serve as President
from 1933 to 1945, or that Marilyn Monroe was more ‘real’ than King Kong or Donald
This is not, and is not be intended to be, a general claim that conspiracy theories
are unjustified or unwarranted. Much depends on the background state of knowledge producing
institutions. If those institutions are generally trustworthy, in part because they
are embedded in an open society with a well-functioning marketplace of ideas and free
flow of information, then conspiracy theories will generally (which is not to say always)
be unjustified. On the other hand, individuals in societies with systematically malfunctioning or skewed institutions of knowledge – say, individuals who live in an authoritarian regime lacking a free press – may have good reason to distrust all or most of the official denials they hear. For these individuals, conspiracy theories will more often be warranted, whether or not true.
Likewise, individuals embedded in isolated groups or
small, self-enclosed networks who are exposed only to skewed information will more
often hold conspiracy theories that are justified, relative to their limited informational
environment. Holocaust denials might themselves be considered in this light. When
isolated groups operate within a society that is both wider and more open, their theories
may be unjustified from the standpoint of the wider society but justified from the
standpoint of the group if it maintains its isolation. In these situations, the problem for
the wider society is to breach the informational isolation of the small group or network, a
problem we discuss below.
On our account, a defining feature of conspiracy theories is that they are
extremely resistant to correction, certainly through direct denials or counterspeech by
government officials. Those who accept such theories believe that the agents of the
conspiracy have unusual powers, so that apparently contrary evidence can usually be
shown to be a product of the conspiracy itself. Conspiracy theories display the
characteristic features of a “degenerating research program”24 in which contrary evidence
is explained away by adding epicycles and resisting falsification of key tenets.25 Some
epistemologists argue that this resistance to falsification is not objectionable if one also
believes that there are conspirators deliberately attempting to plant evidence that would
falsify the conspiracy theory.26 However that may be as a philosophical matter, the selfsealing
quality of conspiracy theories creates serious practical problems for government;
direct attempts to dispel the theory can usually be folded into the theory itself, as just one
more ploy by powerful machinators to cover their tracks. A denial may, for example, be
taken as a confirmation. In this way, conspiracy theories create challenges that are
distinct from those posed by false but dangerous beliefs (recall the belief that prolonged
exposure to sunlight is good for you or that climate change is not occurring).
Accordingly, we will focus on indirect means of undermining such theories, principally
by breaking up the closed informational networks that produce such theories.
So far we have discussed some epistemological features of conspiracy theories, in
the abstract. We now turn to the sociology of conspiracy theorizing, examining the
mechanisms by which such theories arise and expand.
B. How Conspiracy Theories Arise and Spread
1. Crippled epistemologies. Why do people accept conspiracy theories that turn
out to be false and for which the evidence is weak or even nonexistent? It is tempting to
answer in terms of individual pathology.27 Perhaps conspiracy theories are a product of
Another common idea treats conspiracy theories as a form of collective paranoid delusion,
mental illness, such as paranoia or narcissism. And indeed, there can be no doubt that
some people who accept conspiracy theories are mentally ill and subject to delusions.28
But we have seen that in many communities and even nations, such theories are widely
held. It is not plausible to suggest that all or most members of those communities are
afflicted by mental illness. The most important conspiracy theories are hardly limited to
those who suffer from any kind of pathology.
For our purposes, the most useful way to understand the pervasiveness of
conspiracy theories is to examine how people acquire information.29 For most of what
they believe that they know, human beings lack personal or direct information; they must
rely on what other people think. In some domains, people suffer from a “crippled
epistemology,” in the sense that they know very few things, and what they know is
Many extremists fall in this category; their extremism stems not from
irrationality, but from the fact that they have little (relevant) information, and their
extremist views are supported by what little they know.31 Conspiracy theorizing often has
the same feature. Those who believe that Israel was responsible for the attacks of 9/11, or
that the Central Intelligence Agency killed President Kennedy, may well be responding
quite rationally to the informational signals that they receive.
Consider here the suggestive fact that terrorism is more likely to arise in nations
that lack civil rights and civil liberties.32 An evident reason for the connection is that
terrorism is an extreme form of political protest, and when people lack the usual outlets
for registering their protest, they might resort to violence.33 But consider another
possibility: When civil rights and civil liberties are restricted, little information is
available, and what comes from government cannot be trusted. If the trustworthy
information justifies conspiracy theories and extremism, and (therefore?) violence, then
terrorism is more likely to arise.
2. Rumors and speculation. Of course it is necessary to specify how, exactly,
conspiracy theories begin.. Some such theories seem to bubble up spontaneously,
appearing roughly simultaneously in many different social networks; others are initiated
and spread, quite intentionally, by conspiracy entrepreneurs who profit directly or
indirectly from propagating their theories. An example in the latter category is the
34 See W.V. Quine & J.S. Ullian, THE WEB OF BELIEF (2d ed. 1978). On the search for reflective
equilibrium in general, see John Rawls, A THEORY OF JUSTICE (1971).
35 For a classic case study, see Leon Festinger et al., WHEN PROPHECY FAILS (1956). For a general
treatment, see Carol Tavris and Elliot Aronson, MISTAKES WERE MADE (BUT NOT BY ME) (2007).
French author Thierry Meyssan, whose book “9/11: The Big Lie” became a bestseller and
a sensation for its claims that the Pentagon explosion on 9/11 was caused by a missile,
fired as the opening salvo of a coup d’etat by the military-industrial complex, rather than
by American Airlines Flight 77. Some conspiracy entrepreneurs are entirely sincere;
others are interested in money or power, or in achieving some general social goal. Still,
even for conspiracy theories put about by conspiracy entrepreneurs, the key question is
why some theories take hold while many more do not, and vanish into obscurity.
Whenever a bad event has occurred, rumors and speculation are inevitable. Most
people are not able to know, on the basis of personal or direct knowledge, why an
airplane crashed, or why a leader was assassinated, or why a terrorist attack succeeded. In
the aftermath of such an event, numerous speculations will be offered, and some of them
will likely point to some kind of conspiracy. To some people, those speculations will
seem plausible, perhaps because they provide a suitable outlet for outrage and blame,
perhaps because the speculation fits well with other deeply rooted beliefs that they hold.
Terrible events produce outrage, and when people are outraged, they are all the more
likely to attribute those events to intentional action. In addition, antecedent beliefs are a
key to the success or failure of conspiracy theories. Some people would find it impossibly
jarring to think that the CIA was responsible for the assassination of a civil rights leader;
that thought would unsettle too many of their other judgments. Others would find those
other judgments strongly supported, even confirmed, by the suggestion that the CIA was
responsible for such an assassination. Compare the case of terrorist attacks. For most
Americans, a claim that the United States government attacked its own citizens, for some
ancillary purpose, would make it impossible to hold onto a wide range of other
judgments. Clearly this point does not hold for many people in Islamic nations, for whom
it is far from jarring to believe that responsibility lies with the United States (or Israel).
Here, as elsewhere, people attempt to find some kind of equilibrium among their
assortment of beliefs,34 and acceptance or rejection of a conspiracy theory will often
depend on which of the two leads to equilibrium. Some beliefs are also motivated, in the
sense that people are pleased to hold them or displeased to reject them.35 Acceptance (or
for that matter rejection) of a conspiracy theory is frequently motivated in that sense.
Reactions to a claim of conspiracy to assassinate a political leader, or to commit or to
allow some atrocity either domestically or abroad, are often determined by the
motivations of those who hear the claim.
These are points about individual judgments, bracketing social influences. But
after some bad event has occurred, those influences are crucial, for most people will have
little or no direct information about its cause. How many people know, directly or on the
basis of personal investigation, whether Al Qaeda was responsible for the 9/11 attacks, or
whether Lee Harvey Oswald killed President Kennedy on his own, or whether a tragic
death in an apparent airplane accident was truly accidental? Inevitably people must rely
36 For general discussion of the importance of thresholds, see Marc Granovetter, Threshold Models of
Collective Behavior, 83 AM. J. SOC. 1420 (1978).
on the beliefs of other people. Some people will require a great deal of evidence in order
to accept a conspiracy theory; others will require much less. People will therefore have
different “thresholds” for accepting or rejecting such a theory and for acting on the basis
of the theory.36 One way to meet a relevant threshold is to supply direct or indirect
evidence. Another way is simply to show that some, many, or most (trusted) people
accept or reject the theory. These are the appropriate circumstances for social cascades, in
particular informational cascades, whose dynamics help to explain the pervasive
acceptance of conspiracy theories.
3. Conspiracy cascades, 1: the role of information. To see how informational
cascades work, imagine a group of people who are trying to assign responsibility for
some loss of life. Assume that the group members are announcing their views in
sequence. Each member attends, reasonably enough, to the judgments of others.
Andrews is the first to speak. He suggests that the event was caused by a conspiracy of
powerful people. Barnes now knows Andrews’s judgment; she should certainly go along
with Andrew’s account if she agrees independently with him. But if her independent
judgment is otherwise, she would—if she trusts Andrews no more and no less than she
trusts herself—be indifferent about what to do, and she might simply flip a coin.
Now turn to a third person, Charleton. Suppose that both Andrews and Barnes have
endorsed the conspiracy theory, but that Charleton’s own view, based on limited information, suggests that they are probably wrong. In that event, Charleton might well
ignore what he knows and follow Andrews and Barnes. It is likely, after all, that both
Andrews and Barnes had evidence for their conclusion, and unless Charleton thinks that
his own information is better than theirs, he should follow their lead. If he does,
Charleton is in a cascade. Of course Charleton will resist if he has sufficient grounds to
think that Andrews and Barnes are being foolish. But if he lacks those grounds, he is
likely to go along with them.
Now suppose that Charleton is speaking in response to what Andrews and Barnes
did, not on the basis of his own information, and also that later people know what
Andrews, Barnes, and Charleton said. On reasonable assumptions, they will reach the
same conclusion regardless of their private information (which, we are supposing, is
relevant but inconclusive). This will happen even if Andrews initially speculated in a
way that does not fit the facts. That initial speculation, in this example, can start a process
by which a number of people are led to participate in a cascade, accepting a conspiracy
theory whose factual foundations are fragile.
Of course the example is highly stylized and in that sense unrealistic; conspiracy
cascades arise through more complex processes, in which diverse thresholds are
important. In a standard pattern, the conspiracy theory is initially accepted by people with
low thresholds for its acceptance. Sometimes the informational pressure builds, to the
point where many people, with somewhat higher thresholds, begin to accept the theory
too. As a real-world example of a conspiracy cascade, consider the existence of certain
37 See Fabio Lorenzi-Cioldi & Alain Clémence, Group Processes and the Construction of Social
Representations, in GROUP PROCESSES, at 311, 315–17 (Michael A. Hogg & R. Scott Tindale eds., 2001).
38 See Punctuated Equilibrium and the Dynamics of U.S. Environmental Policy (Robert Repetto ed. 2006);
Timur Kuran and Cass R. Sunstein, Availability Cascades and Risk Regulation, 51 STAN. L. REV. 683
judgments about the origins and causes of AIDS, with some groups believing,
implausibly, that the virus was produced in government laboratories.37 These and other
views about AIDS are a product of social interactions and in particular of cascade effects.
4. Conspiracy cascades, 2: the role of reputation. Conspiracy theories do not take
hold only because of information. Sometimes people profess belief in a conspiracy
theory, or at least suppress their doubts, because they seek to curry favor. Reputational
pressures help account for conspiracy theories, and they feed conspiracy cascades.
In a reputational cascade, people think that they know what is right, or what is likely
to be right, but they nonetheless go along with the crowd in order to maintain the good
opinion of others. Suppose that Albert suggests that the Central Intelligence Agency was
responsible for the assassination of President Kennedy, and that Barbara concurs with
Albert, not because she actually thinks that Albert is right, but because she does not wish
to seem, to Albert, to be some kind of dupe. If Albert and Barbara say that the CIA was
responsible for the assassination of President Kennedy, Cynthia might not contradict
them publicly and might even appear to share their judgment — not because she believes
that judgment to be correct, but because she does not want to face their hostility or lose
their good opinion. It should be easy to see how this process might generate a cascade.
Once Albert, Barbara, and Cynthia offer a united front on the issue, their friend David
might be reluctant to contradict them even if he thinks that they are wrong. The
apparently shared view of Albert, Barbara, and Cynthia carry information; that view
might be right. But even if David has reason to believe that they are wrong, he might not
want to take them on publicly. His own silence will help build the informational and
reputational pressure on those who follow.
5. Conspiracy cascades, 3: the role of availability. Informational and reputational
cascades can occur without any particular triggering event. But a distinctive kind of
cascade arises when such an event is highly salient or cognitively “available.” In the
context of many risks, such as those associated with terrorism, nuclear power, and
abandoned hazardous waste dumps, a particular event initiates a cascade, and it stands as
a trigger or a symbol justifying public concern, whether or not that concern is
warranted.38 Availability cascades occur through the interaction between a salient event
and social influences, both informational and reputational. Often political actors, both
self-interested and altruistic, work hard to produce such cascades.
Conspiracy theories are often driven through the same mechanisms. A particular
event becomes available, and conspiracy theories are invoked both in explaining it and
using it as a symbol for broader social forces, casting doubt on accepted wisdom in many
domains. Within certain nations and groups, the claim that the United States or Israel was
responsible for the attacks of 9/11 fits well within a general narrative about who is the
39 See ROGER BROWN, SOCIAL PSYCHOLOGY: THE SECOND EDITION 202–26 (2003).
40 See id. at 204.
41 Id. at 223–24.
42 See id. at 212–22, 226–45; Robert S. Baron & Norbert L. Kerr, GROUP PROCESS, GROUP DECISION,
GROUP ACTION (2d ed. 2001), at 540.
43 See Cass R. Sunstein, WHY SOCIETIES NEED DISSENT (2003).
aggressor, and the liar, in a series of disputes – and the view that Al Qaeda was
responsible raises questions about that same narrative. Conspiracy theories are frequently
a product of availability cascades.
6. Group polarization. There are clear links between cascades and the wellestablished
phenomenon of group polarization, by which members of a deliberating
group typically end up in a more extreme position in line with their tendencies before
deliberation began.39 Group polarization has been found in hundreds of studies involving
over a dozen countries.40 Belief in conspiracy theories is often fueled by group
Consider, as the clearest example, the finding that those who disapprove of the
United States, and are suspicious of its intentions, will increase their disapproval and
suspicion if they exchange points of view. There is specific evidence of this phenomenon among citizens of France: With respect to foreign aid, they trust the United States a great deal less, and suspect its intentions a great deal more, after they talk with one another.41 It should be easy to see how similar effects could occur for conspiracy theories. Those who tend to think that Israel was responsible for the attacks of 9/11, and who speak with one another, will end up with a greater commitment to that belief.
Group polarization occurs for reasons that parallel the mechanisms that produce
cascades.42 Informational influences play a large role. In any group with some initial
inclination, the views of most people in the group will inevitably be skewed in the
direction of that inclination. As a result of hearing the various arguments, social
interactions will lead people toward a more extreme point in line with what group
members initially believed. Reputational factors matter as well. People usually want to be perceived favorably by other group members. Once they hear what others believe, some will adjust their positions at least slightly in the direction of the dominant position.
For purposes of understanding the spread of conspiracy theories, it is especially important to note that group polarization is particularly likely, and particularly pronounced, when people have a shared sense of identity and are connected by bonds of solidarity.43
These are circumstances in which arguments by outsiders, unconnected with the group, will lack much credibility, and fail to have much of an effect in reducing polarization. As we will explore below, these circumstances imply that direct government rebuttals of the reigning conspiracy theory will prove ineffective; government will instead do best by using various tactics of cognitive infiltration to break up the polarized information cluster from within.
7. Selection effects. A crippled epistemology can arise not only from informational
and reputational dynamics within a given group, but also from self-selection of members
44 Hardin, supra note 30, at 9-12.
45 Id. at 10.
46 Id. at 11; Hofstadter, supra note 27.
47 Roderick M. Kramer, The Sinister Attribution Error: Paranoid Cognition and Collective Distrust in
Organizations, 18 MOTIVATION & EMOTION 199, 199-230 (1994).
into and out of groups with extreme views.44 Once polarization occurs or cascades arise,
and the group’s median view begins to move in a certain direction, doubters and halfwaybelievers will tend to depart while intense believers remain. The overall size of the group may shrink, but the group may also pick up new believers who are even more committed,
and in any event the remaining members will, by self-selection, display more fanaticism.
Group members may engage in a kind of double-think, segregating themselves, in a
physical or informational sense, in order to protect their beliefs from challenge by
outsiders.45 Even if the rank and file cannot coherently do this, group leaders may
enforce segregation in order to insulate the rank and file from information or arguments
that would undermine the leaders’ hold on the group.
Members of informationally and socially isolated groups tend to display a kind of
paranoid cognition 46 and become increasingly distrustful or suspicious of the motives of others or of the larger society, falling into a “sinister attribution error.”47 This error
occurs when people feel that they are under pervasive scrutiny, and hence they attribute
personalistic motives to outsiders and overestimate the amount of attention they receive.
Benign actions that happen to disadvantage the group are taken as purposeful plots,
intended to harm.48
Although these conditions resemble individual-level pathologies, they arise from the social and informational structure of the group, especially those operating in enclosed or closely knit networks, and are not usefully understood as a form of mental illness. The social etiology of such conditions suggests that the appropriate remedy is not individual treatment, but the introduction of cognitive, informational, and social diversity into the isolated networks that supply extremist theories. We take up the resulting policy problems in the next Part.
II. Governmental Responses
What can government do about conspiracy theories? Among the things it can do,
what should it do? We can readily imagine a series of possible responses.
(1) Government might ban conspiracy theorizing.
(2) Government might impose some kind
of tax, financial or otherwise, on those who disseminate such theories.
(3) Government might itself engage in counterspeech, marshaling arguments to discredit conspiracy theories.
(4) Government might formally hire credible private parties to engage in
(5) Government might engage in informal communication with such
parties, encouraging them to help. Each instrument has a distinctive set of potential
effects, or costs and benefits, and each will have a place under imaginable conditions.
However, our main policy idea is that government should engage in cognitive infiltration of the groups that produce conspiracy theories, which involves a mix of (3), (4) and (5).
If one believes that conspiracy theories are in some sense inconsequential, the
best answer will be for government to ignore them. If children believe in Santa Claus or
the Easter Bunny, there is no problem for government to solve; and the belief that the
49 On those benefits in general, see Scott Page, THE DIFFERENCE (2006).
government covered up the landing of space aliens in Roswell does not seem to be
causing discernible harm, with the possible exception of bad television shows. (This does
not imply that government should ignore conspiracy theories only if they are
inconsequential. As we will see, under certain conditions government may do best to
ignore conspiracy theories and theorists even if it justifiably fears that they will have
harmful effects, because government action may make things worse.) In Section A,
however, we give some reasons to think that some conspiracy theories are consequential
In Section B, we address several dilemmas of governmental response to
conspiracy theories and theorists. Is it best to ignore them, creating a risk that the theory
will spread unrebutted, or to address them, with the risk that addressing the theory will
legitimate and even be taken to confirm it? Assuming budget constraints and limited
resources, should government efforts focus on debiasing the conspiracy theorists
themselves, or solely on preventing the spread of conspiracy theories among the larger
population? How can government get behind or around the distinctive feature of
conspiracy theories — their self-sealing quality, which tends to fold government’s denials
into the theory itself as further evidence of the conspiracy?
An obvious answer is to maintain an open society, in which those who are
tempted to subscribe to conspiracy theories do not distrust all knowledge-creating
institutions, and are exposed to corrections. But we have seen that even in open societies,
conspiracy theories have some traction; and open societies have a strong interest in
debunking such theories when they arise, and threaten to cause harm, in closed societies.
Here we suggest two concrete ideas for government officials attempting to fashion a
response to such theories.
First, responding to more rather than fewer conspiracy theories has a kind of synergy benefit: it reduces the legitimating effect of responding to any one of them, because it dilutes the contrast with unrebutted theories.
Second, we suggest a distinctive tactic for breaking up the hard core of extremists who supply conspiracy theories: cognitive infiltration of extremist groups, whereby government agents or their allies (acting either virtually or in real space, and either openly or anonymously) will
undermine the crippled epistemology of those who subscribe to such theories. They do so
by planting doubts about the theories and stylized facts that circulate within such groups,
thereby introducing beneficial cognitive diversity.49
In Section C, we examine the role of law and judges in fashioning the
government’s response. We will ask whether judges do more good than harm by
invoking statutes such as the Freedom of Information Act to force government to disclose
facts that would rebut conspiracy theories. Our conclusions are generally skeptical: there
is little reason to believe that judges can improve on administrative choices in these
situations. Section D concludes with some brief notes on government efforts to dispel
conspiracy theories held by foreign audiences, especially in Muslim countries.
Throughout, we assume a well-motivated government that aims to eliminate
conspiracy theories, or draw their poison, if and only if social welfare is improved by
doing so. (We do not offer a particular account of social welfare, taking the term instead
as a placeholder for the right account.) This is a standard assumption in policy analysis,
50 See Scott Macleod, Suspicious Minds; In the Arab World, Conspiracy Theories and Rising Anti-Semitism
Deflect Attention From Real Problems, TIME, June 17, 2002, at 28.
51 See, e.g., Frank Rich, Editorial, Dishonest, Reprehensible, Corrupt, N.Y. TIMES, Nov. 27, 2005, at 11
(“Nonetheless Mr. Bush and Mr. Cheney repeatedly pounded in an implicit (and at times specific) link
between Saddam and Al Qaeda until Americans even started to believe that the 9/11 attacks had been
carried out by Iraqis.”).
52 See Clarke, supra note 24, at 91 (noting that “few [conspiracy theories] are actually harmful”).
53 Jon Elster, EXPLAINING SOCIAL BEHAVIOR (2007); Bryan Caplan, THE MYTH OF THE RATIONAL VOTER
54 Richard Cohen, Editorial, The Making of a Conspiracy Theory, WASH. POST, Dec. 23, 2003, at A21; see
also Andrea Stone, In Poll, Islamic World Says Arabs Not Involved in 9/11, USA TODAY, Feb. 27, 2002, at
and is useful for clarifying the policy questions, but we note that real-world governments
can instead be purveyors of conspiracy theories. In Egypt, newspapers effectively
controlled by the governing regime regularly spread conspiracy theories about Jews.50
Some believe that the Bush administration deliberately spread a kind of false and
unwarranted conspiracy theory – that Saddam Hussein conspired with Al Qaeda to
support the 9/11 attacks.51 Suppose for discussion’s sake that this is so; then a future
administration motivated to improve social welfare would need to consider whether this
theory is false and harmful, and if it is what can and should be done about it. But this
would just be another case of a conspiracy theory circulating in the population, which
might or might not be worth responding to, in light of the considerations we adduce
below. Nothing of theoretical interest follows from this case for the questions we address
here, which strictly involve optimal responses to conspiracy theories on the part of a (real
or imagined) well-motivated government.
A. Are Conspiracy Theories Consequential?
One line of thinking denies that conspiracy theories matter.52 There are several
possible reasons to think so. First, conspiracy theories may be held by only a tiny
fraction of the population. Perhaps only a handful of kooks believe that U.S. government
officials had any kind of role in the events of 9/11. Second, even if a particular
conspiracy theory is widely held in the sense that many people will confess to it when
polled, conspiracy theories may typically be held as “quasi-beliefs” – beliefs that are not
costly and possibly even fun to hold, like a belief in aliens in Roswell or UFOs, and that
do not form a premise for action.53 Many people profess to believe, and in some sense do
believe, that eternal life depends upon actions that they do not take. So too, perhaps
many people quasi-believe in conspiracy theories yet do not take action on account of
In both cases everything depends, of course, on which conspiracy theory and
which population one is discussing. However, as discussed in Part I, there is ample
evidence that some conspiracy theories are not at all confined to small segments of the
population. Overseas, “a 2002 Gallup Poll conducted in nine Islamic countries found that
61 percent of those surveyed thought that Muslims had nothing to do with the attacks of
Sept. 11, 2001.”54 According to an anonymous State Department official in charge of
anti-disinformation, “a great deal of harm can result ‘when people believe these lies and
55 William Weir, Damage Control; State Department Officer Works To Dispel Lies, Conspiracy Theories
and Urban Legends That Harm U.S. Image, HARTFORD COURANT, Oct. 16, 2006, at D1.
56 James D. Fearon, Catastrophic Terrorism and Civil Liberties (unpublished draft), available at
57 See Cass R. Sunstein, WORST-CASE SCENARIOS (2007).
then act on the basis of their mistaken beliefs.’” For example, “Al-Qaeda members ‘were
encouraged to join the jihad at least in part because of disinformation.’”55
The point about quasi-beliefs suggests that many do not in fact take any action on
the basis of their mistaken beliefs. However, this does not at all entail that conspiracy
theories are inconsequential. Even if only a small fraction of adherents to a particular
conspiracy theory act on the basis of their beliefs, that small fraction may be enough to
cause serious harms. Consider the Oklahoma City bombing, whose perpetrators shared a
complex of conspiratorial beliefs about the federal government. Many who shared their
beliefs did not act on them, but a few actors did, with terrifying consequences. James
Fearon and others argue that technological change has driven down the costs of
delivering attacks with weapons of mass destruction, to the point where even a small
group can pose a significant threat.56 If so, and if only a tiny fraction of believers act on
their beliefs, then as the total population with conspiratorial beliefs grows, it becomes
nearly inevitable that action will ensue.
In cases of this sort, the conspiracy theory itself supports affirmatively violent
action on the part of its believers (which only a small fraction will actually take);
conspiracy theorizing leads to an actual conspiracy. Within a network whose members
believe that the federal government, say, is a hostile and morally repellent organization
that is taking over the country, akin to a foreign invader, armed resistance will seem a
sensible course to at least some fraction of the believers. In other, perhaps more
common, cases the conspiracy theory will be of a different nature and will not directly
indicate such action. However, such theories can still have pernicious effects from the
government’s point of view, either by inducing unjustifiably widespread public
skepticism about the government’s assertions, or by dampening public mobilization and
participation in government-led efforts, or both. The widespread belief that U.S. officials
knowingly allowed 9/11 to happen or even brought it about may have hampered the
government’s efforts to mobilize social resources and political support for measures
against future terrorist attacks.
In the nature of things it is hard to find evidence for, or against, such possibilities;
yet it hardly seems sensible to say that because such evidence is lacking, government
should do nothing about a potentially harmful conspiracy theory. That precept would be
paralyzing, because there are uncertain harms on all sides of the question, and because –
as in the case of the Oklahoma City bombing – some of those harms may approach the
B. Dilemmas and Responses
Imagine a government facing a population in which a particular conspiracy theory
is becoming widespread. We will identify two basic dilemmas that recur, and consider
how government should respond. The first dilemma is whether to ignore or rebut the
theory; the second is whether to address the supply side of conspiracy theorizing by
58 For relevant discussion, see Glaeser, The Political Economy of Hatred, supra note.
59 See Timur Kuran, PRIVATE TRUTHS, PUBLIC LIES (1998).
attempting to debias or disable its purveyors, to address the demand side by attempting to
immunize third-party audiences from the theory’s effects, or to do both (if resource
In both cases, the underlying structure of the problem is that conspiracy theorizing
is a multi-party game. Government is faced with suppliers of conspiracy theories, and
might aim at least in part to persuade, debias, or silence those suppliers. However, those
two players are competing for the hearts and minds of third parties, especially the mass
audience of the uncommitted.58
Expanding the cast further, one may see the game as involving four players: government officials, conspiracy theorists, mass audiences, and independent experts – such as mainstream scientists or the editors of Popular Mechanics – whom government attempts to enlist to give credibility to its rebuttal efforts. The discussion that follows generally assumes the three-party structure, but we will refer to the four-party structure when relevant.
1. Ignore or rebut?
The first dilemma is that either ignoring or rebutting a conspiracy theory has
distinctive costs. Ignoring the theory allows its proponents to draw ominous inferences
from the government’s silence. If the theory stands unrebutted, one possibility is that it is
too ludicrous to need rebuttal, but another is that the government cannot offer relevant
evidence to the contrary; the suppliers of the conspiracy theories will propose the second
inference. On this view, all misinformation (the initial conspiracy theory) should be met
On the other hand, to rebut the theory may be to legitimate it, moving the theory
from the zone of claims too ludicrous to be discussed to the zone of claims that, whether
or not true, are in some sense worth discussing. This legitimating effect can arise in one
of two ways. First, third-party audiences may infer from the government’s rebuttal
efforts that the government estimates the conspiracy theory to be plausible, and fears that
the third parties will themselves be persuaded. Second, some members of the audience
may infer that many other members of the audience must believe the theory, or
government would not be taking the trouble to rebut it. Consider circumstances of
“pluralistic ignorance,” in which citizens are unsure what other citizens believe.59
Citizens may take the fact of rebuttal itself as supplying information about the beliefs of
other citizens, and may even use this information in forming their own beliefs. The
government’s rebuttal may be a signal that other citizens believe in the conspiracy theory
– and may therefore make the theory more plausible. If the number who follow this
cognitive strategy and thus adopt a belief in the theory exceeds the number who are
persuaded by the rebuttal, the perverse result of the rebuttal may then be to increase the
number of believers.
How should government cope with this dilemma? In a typical pattern,
government plays a wait-and-see strategy: ignore the conspiracy theory until it reaches
some ill-defined threshold level of widespread popularity, and then rebut. There is a
straightforward logic to this strategy. First, when the government ignores the theory,
either the relevant audiences will draw an inference that the theory is silly, or else will
60 See Avinash K. Dixit & Robert S. Pindyck, INVESTMENT UNDER UNCERTAINTY (1994).
infer that the government cannot effectively deny it. If the conspiracy theory does not
spread despite government’s silence, the former inference is probably dominant, and
response is unnecessary. Second, there is an option value60 to the strategy of ignoring the
theory: a public rebuttal now is costly or impossible to undo, but maintaining silence now
leaves government with the option to rebut later, if it chooses to do so. On this approach,
when faced with a spreading conspiracy theory, government should wait until the
marginal expected benefits of further delay just equal the marginal expected costs of
leaving the theory unrebutted. Finally and most generally, it seems silly and infeasible to
chase after and rebut every conspiracy theory that comes to government’s attention.
However, this logic overlooks an important synergistic gain: rebutting many
conspiracy theories can reduce the legitimating effect of rebutting any one of them.
When government rebuts a particular theory while ignoring most others, the legitimating
effect arises at least in part because of a contrast between the foreground and the
background: the inference is that government has picked the theory it is rebutting out of
the larger set because this theory, unlike the others, is inherently plausible or is gaining
traction among some sectors of the mass audience. Rebutting a larger fraction of the total
background set reduces the strength of this inference as to each theory chosen for
rebuttal. The more theories government rebuts, the weaker is the implicit legitimating
signal sent by the very fact of rebuttal.
It is impossible to say, in the abstract, how great this synergistic gain may be. It
remains true that not every conspiracy theory proposed by someone somewhere (that
comes to the attention of relevant government officials) warrants a response. However,
the implication is that government should rebut more conspiracy theories than it would
otherwise choose, if assessing the expected costs and benefits of rebuttal on a theory-bytheory
basis. Because of synergy effects, government action considered over an array or
range of cases may have different total costs and benefits than when those cases are
considered one by one. Practically speaking, government might do well to maintain a
more vigorous countermisinformation establishment than it would otherwise do, one that
identifies and rebuts many more conspiracy theories would otherwise be rebutted. There
will still have to be some minimum threshold for governmental response, but the
threshold will be lower than it would be if this synergistic gain of rebutting many theories
did not exist.
2. Which audience?
Another dilemma is whether to target the supply side of the conspiracy theory or
the demand side. Should governmental responses be addressed to the suppliers, with a
view to persuading or silencing them, or rather be addressed to the mass audience, with a
view to inoculating them from pernicious theories? Of course these two strategies are not
mutually exclusive as a logical matter; perhaps the best approach is to straddle the two
audiences with a single response or simply to provide multiple responses. However, if
there are resource constraints, government may face a choice about where to place its
emphases. The question will be what mix of second-party responses (pitched to the
suppliers) and third-party responses (pitched to the mass audience) is best. Moreover,
apart from resource constraints, there are intrinsic tradeoffs across these strategies. The
61 Cf. LEON FESTINGER ET AL., WHEN PROPHECY FAILS, supra note 35.
62 DEBUNKING 9/11 MYTHS: WHY CONSPIRACY THEORIES CAN’T STAND UP TO THE FACTS 60-61 (David
Dunbar & Brad Reagan eds., 2006).
63 See, e.g., Jim Hoffman, Video of the Pentagon Attack: What Is the Government Hiding,
http://911research.com/essays/pentagon/video.html (last visited Nov. 14, 2006).
very arguments that are most convincing to the mass audience may be least convincing to
the conspiracists, and vice-versa.
We will begin with some remarks about responses addressed to the supply side.
The basic problem with pitching governmental responses to the suppliers of conspiracy
theories is that those theories, by their nature, have a self-sealing quality. They are (1)
resistant and in extreme cases invulnerable to contrary evidence,61 and (2) especially
resistant to contrary evidence offered by the government, because the government
rebuttal is folded into the conspiracy theory itself. If conspiracy theorists are responding
to the informational signals given by those whom they trust, then the government’s effort
at rebuttal seems unlikely to be effective, and might serve to fortify rather than to
undermine the original belief. (A possible solution is for government to enlist private
rebuttals; we return to this point shortly.) The most direct response to a dangerous
conspiracy theories is censorship. That response is unavailable in an open society,
because it is inconsistent with principles of freedom of expression. We could imagine
circumstances in which a conspiracy theory became so pervasive, and so dangerous, that
censorship would be thinkable. But in an open society, the need for censorship would be
correspondingly reduced. In any case censorship may well turn out to be self-defeating.
The effort to censor the theory might well be taken as evidence that the theory is true, and
censorship of speech is notoriously difficult.
After 9/11, one complex of conspiracy theories involved American Airlines Flight
77, which hijackers crashed into the Pentagon. Some theorists claimed that no plane had
hit the Pentagon; even after the Department of Defense released video frames showing
Flight 77 approaching the building and a later explosion cloud, theorists pointed out that
the actual moment of impact was absent from the video, in order to keep alive their claim
that the plane had never hit the building. (In reality the moment of impact was not
captured because the video had a low number of frames per second.62) Moreover, even
those conspiracists who were persuaded that the Flight 77 conspiracy theories were
wrong folded that view into a larger conspiracy theory. The problem with the theory that
no plane hit the Pentagon, they said, is that the theory was too transparently false,
disproved by multiple witnesses and much physical evidence. Thus the theory must have
been a straw man initially planted by the government, in order to discredit other
conspiracy theories and theorists by association.63
Government can partially circumvent these problems if it enlists nongovernmental
officials in the effort to rebut the theories. It might ensure that credible independent
experts offer the rebuttal, rather than government officials themselves. There is a
tradeoff between credibility and control, however. The price of credibility is that
government cannot be seen to control the independent experts. Although government can
supply these independent experts with information and perhaps prod them into action
from behind the scenes, too close a connection will prove self-defeating if it is exposed –
as witness the humiliating disclosures showing that apparently independent opinions on
64 See Ian Sample, Scientists Offered Cash To Dispute Climate Study, GUARDIAN, Feb. 2, 2007, at 1 (noting
that a “thinktank with close links to the Bush administration” had paid scientists to challenge a report on
65 In fact the two may be distant relatives, but had never met. Will Sullivan, Viewing 9/11 From a Grassy
Knoll, U.S. NEWS & WORLD REP., Sept. 11, 2006.
66 Carol Morello, One Man’s Unorthodox Ideas About the 9/11 Attack on the Pentagon Go Global in a
Flash. Welcome to the Internet, Where Conspiracy Theories Flourish., WASH. POST, Oct. 7, 2004, at B01.
67 Jim Dwyer, U.S. Counters 9/11 Theories of Conspiracy, N.Y. TIMES, Sept. 2, 2006, at B1.
scientific and regulatory questions were in fact paid for by think-tanks with ties to the
Bush administration.64 Even apart from this tradeoff, conspiracy theorists may still fold
independent third-party rebuttals into their theory by making conspiratorial claims of
connection between the third party and the government. When Popular Mechanics
offered its rebuttal of 9/11 conspiracy theories, conspiracists claimed that one of the
magazine’s reporters, Ben Chertoff, was the cousin of Homeland Security Secretary
Michael Chertoff and was spreading disinformation at the latter’s behest.65
Because of these difficulties, many officials dismiss direct responses to the
suppliers of conspiracy theorists as an exercise in futility. Rather, they implicitly frame
their responses to the third-party mass audience, hoping to stem the spread of conspiracy
theories by dampening the demand rather than by reducing the supply. Philip Zelikow,
the executive director of the 9/11 commission, says that “[t]he hardcore conspiracy
theorists are totally committed. They’d have to repudiate much of their life identity in
order not to accept some of that stuff. That’s not our worry. Our worry is when things
become infectious . . . . [t]hen this stuff can be deeply corrosive to public understanding.
You can get where the bacteria can sicken the larger body.”66 Likewise, when the
National Institute of Standards and Technology issued a fact sheet to disprove the theory
that the World Trade Center was brought down by a controlled demolition, the
spokesman stated that “[w]e realize this fact sheet won’t convince those who hold to the
alternative theories that our findings are sound. In fact, the fact sheet was never intended
for them. It is for the masses who have seen or heard the alternative theory claims and
The problem with this line of argument, however, is that it takes the existence of a
hard core as a given. This is premature; we will suggest below that if the hard core arises
for certain identifiable reasons, it can be broken up or at least muted by government
action. Furthermore, there are intrinsic costs to the strategy of giving up on the hard core
and directing government efforts solely towards inoculating the mass audience. For one
thing, the hard core may itself provide the most serious threat. For another, a response
geared to a mass audience (whether or not nominally pitched as a response to the
conspiracy theorists) will lead some to embrace rather than reject the conspiracy theory
the government is trying to rebut. This is the legitimation dilemma again: to begin a
program of inoculation is to signal that the disease is already widespread and threatening.
Under pluralistic ignorance, the perverse result may actually be to spread the conspiracy
3. Cognitive infiltration
Rather than taking the continued existence of the hard core as a constraint, and
addressing itself solely to the third-party mass audience, government might undertake
68 Neil MacFarquhar, At State Dept., Blog Team Joins Muslim Debate, N.Y. TIMES, Sept. 22, 2007, at A1.
(legal) tactics for breaking up the tight cognitive clusters of extremist theories, arguments
and rhetoric that are produced by the hard core and reinforce it in turn. One promising
tactic is cognitive infiltration of extremist groups. By this we do not mean 1960s-style
infiltration with a view to surveillance and collecting information, possibly for use in
future prosecutions. Rather, we mean that government efforts might succeed in
weakening or even breaking up the ideological and epistemological complexes that
constitute these networks and groups.
How might this tactic work? Recall that extremist networks and groups,
including the groups that purvey conspiracy theories, typically suffer from a kind of
crippled epistemology. Hearing only conspiratorial accounts of government behavior,
their members become ever more prone to believe and generate such accounts.
Informational and reputational cascades, group polarization, and selection effects suggest
that the generation of ever-more-extreme views within these groups can be dampened or
reversed by the introduction of cognitive diversity. We suggest a role for government
efforts, and agents, in introducing such diversity. Government agents (and their allies)
might enter chat rooms, online social networks, or even real-space groups and attempt to
undermine percolating conspiracy theories by raising doubts about their factual premises,
causal logic or implications for political action.
In one variant, government agents would openly proclaim, or at least make no
effort to conceal, their institutional affiliations. A recent newspaper story recounts that
Arabic-speaking Muslim officials from the State Department have participated in
dialogues at radical Islamist chat rooms and websites in order to ventilate arguments not
usually heard among the groups that cluster around those sites, with some success.68 In
another variant, government officials would participate anonymously or even with false
identities. Each approach has distinct costs and benefits; the second is riskier but
potentially brings higher returns. In the former case, where government officials
participate openly as such, hard-core members of the relevant networks, communities and
conspiracy-minded organizations may entirely discount what the officials say, right from
the beginning. The risk with tactics of anonymous participation, conversely, is that if the
tactic becomes known, any true member of the relevant groups who raises doubts may be
suspected of government connections. Despite these difficulties, the two forms of
cognitive infiltration offer different risk-reward mixes and are both potentially useful
There is a similar tradeoff along another dimension: whether the infiltration
should occur in the real world, through physical penetration of conspiracist groups by
undercover agents, or instead should occur strictly in cyberspace. The latter is safer, but
potentially less productive. The former will sometimes be indispensable, where the
groups that purvey conspiracy theories (and perhaps themselves formulate conspiracies)
formulate their views through real-space informational networks rather than virtual
networks. Infiltration of any kind poses well-known risks: perhaps agents will be asked
to perform criminal acts to prove their bona fides, or (less plausibly) will themselves
become persuaded by the conspiratorial views they are supposed to be undermining;
perhaps agents will be unmasked and harmed by the infiltrated group. But the risks are
69 See SUNSTEIN, supra note 43.
70 See Federal Election Comm’n v. Akins, 524 U.S. 11 (1998).
71 See Jerry Markon, Pentagon Releases Videos of 9/11 Plane Crash; Group Wanted to Counter 9/11
Conspiracy Theories, WASH. POST, May 17, 2006, at B01.
generally greater for real-world infiltration, where the agent is exposed to more serious
All these risk-reward tradeoffs deserve careful consideration. Particular tactics
may or may not be cost-justified under particular circumstances. Our main suggestion is
just that, whatever the tactical details, there would seem to be ample reason for
government efforts to introduce some cognitive diversity into the groups that generate
conspiracy theories. Social cascades are sometimes quite fragile, precisely because they
are based on small slivers of information. Once corrective information is introduced,
large numbers of people can be shifted to different views. If government is able to have
credibility, or to act through credible agents, it might well be successful in dislodging
beliefs that are held only because no one contradicts them. Likewise, polarization tends
to decrease when divergent views are voiced within the group.69 Introducing a measure
of cognitive diversity can break up the epistemological networks and clusters that supply
C. A Role for Law, and Courts?
So far we have detailed some dilemmas facing government officials and have
suggested some policy responses. What if anything is the role of law, and courts, in these
matters? The principal point of contact between the legal system and the issues discussed
here is the Freedom of Information Act (FOIA), which creates a presumption of
transparency for documents held by administrative agencies and executive institutions.
Unless the government can show that the requested information falls within one of a
designated list of exceptions, there is a legal right to disclosure, and the Supreme Court
has created a broad concept of “informational standing”70 to permit interested groups and
citizens to enforce that right.
FOIA becomes relevant when the government holds, and declines to disclose,
information that might rebut a circulating conspiracy theory. An example involves the
disclosure of the Department of Defense video involving Flight 77’s crash into the
Pentagon on 9/11. A pro-transparency group, Judicial Watch, filed a FOIA request to
obtain the video, but the Defense Department declined, saying that the video was to be
used in the trial of Zacharias Moussaoui. Judicial Watch filed suit to force disclosure,
with the avowed objective of using the video to rebut the conspiracy theories surrounding
Flight 77. However, when the Moussaoui trial ended the government released the video
before the lawsuit could be decided.71
The details of the case only suggest the larger question that it poses: should
courts, and law, force the executive to disclose information that a litigant claims would
help to rebut conspiracy theories? If the answer is yes, then control over the timing and
nature of the executive’s responsive strategy will be partially transferred to litigating
groups and judges. If the answer is no, the executive will retain full control.
We suggest that the critical question is a comparative institutional one. Will
adding judicial involvement, itself partially determined by the decisions of litigating
72 In theory courts might do so by reducing the variance associated with these decisions – fewer big
mistakes in either direction – but we will ignore this possibility, which is never adduced to support judicial
intervention. Rather, the standard claim is that government errs systematically, in a particular direction –
73 Cf. Kenneth A. Shepsle, Congress is a “They,” Not an “It”: Legislative Intent as Oxymoron, 12 INT’L
REV. L. & ECON. 239 (1992).
groups, create a net improvement in the government’s overall response strategy? In
general, two conditions must hold for this to be so. First, there must be some mechanism
that causes the executive systematically to make suboptimal decisions about whether,
when, and how to release information that might rebut conspiracy theories. If executive
branch decisions are unbiased, in the sense that they are accurate on average (even if
randomly mistaken in particular cases), then courts will be hard pressed to improve upon
them.72 Second, even if the executive branch does make predictable errors, the litigation
process must have some relative institutional advantage in this regard; it must be able to
improve upon the executive’s choices. The benchmark is not optimal disclosure, but the
disclosure that actually results from adding litigation-based oversight to executive branch
There is little reason to think, in general, that both of these conditions will usually
be met. In the Flight 77 case, Judicial Watch offered no concrete reason why the
executive would erroneously balance the relative benefits and costs of disclosing the
information immediately, including (1) the expected gain to the government’s efforts to
rebut the Flight 77 conspiracy theories; (2) the expected costs to national security of
disclosing details about the Department of Defense’s surveillance activities and methods;
and (3) the lost option value of disclosing later, rather than now. Judicial Watch noted
that (2) was low, because most of the information was already public in one way or
another, and this seems plausible. However, (1) was also low. As we have detailed
above, the video’s release did little to squelch the Flight 77 conspiracy theorists, who
promptly folded the video into their theories. Factor (3) is hard to estimate; but it is clear
that when courts require disclosure in such situations, the value of the option to make a
later disclosure is systematically destroyed. Even if the executive would make mistakes
about these factors, viewed in the light of hindsight, it is plausible to think that those
mistakes will tend to be randomly distributed, in part because governmental interests are
on both sides of the balance. In any event, Judicial Watch offered no reason to think that
the litigation process would systematically do better. In general, the argument for
compelled disclosure is strongest when the executive branch is likely to be systematically
biased against disclosure, for self-serving reasons; this is the argument that most
plausibly justifies FOIA itself. When a conspiracy theory is at work, there is unlikely to
be any systematic bias against disclosure, because the executive has a strong incentive to
correct the theory.
To be sure, the first of the two conditions we have mentioned – that executive
branch disclosures are not optimally geared to suppressing conspiracy theories – does
seem plausible under certain conditions. Because the executive is partially a they, not an
it,73 its (their) efforts to respond to conspiracy theories may be hampered by poor
coordination across agencies or executive departments. Perhaps, for example, one
agency holds information that it refuses to disclose or even transmit within the executive
branch, although another agency or another branch of government needs it to combat a
74 CASS R. SUNSTEIN, ONE CASE AT A TIME (1999).
75 DONALD L. HOROWITZ, THE COURTS AND SOCIAL POLICY (1977); Cf. Frank I. Michelman, Politics and
Values or What’s Really Wrong With Rationality Review, 13 Creighton L. Rev. 487 (1979).
76 See, e.g., U.S. Dep’t of Justice v. Reporters Comm. for Freedom of the Press, 489 U.S. 749, 771-73
conspiracy theory. Here there is a kind of intra-executive externality, with one agency
failing to take into account the full costs of its actions to other institutions. Moreover, if
there are systematic incentives for overclassification and excessive government secrecy –
a claim that is often heard but rarely fleshed out with concrete mechanisms – then there
will be systematic error in government responses, with too little disclosure or disclosure
coming too late.
However, these possibilities are balanced by equally speculative possibilities
cutting in other directions. If the executive is a they, not an it, it may also be the case that
a given agency does not fully take into account the harms of disclosure to the mission of
other agencies, and the problem will be too much disclosure or premature disclosure
(from the standpoint of the latter agencies). Intra-executive externalities and agency
incentives may cut in either direction; their net effect is hard to assess in the abstract, and
there is little reason to think they necessarily create a systematic skew in one direction or
another. Furthermore, addressing conspiracy theories is not the only thing the executive
does. Even if an agency is not acting optimally with respect to that goal, it may be acting
in a way that promotes good policy (somehow defined) overall.
Most importantly, there is little general reason to think that the second condition –
that litigating groups and judges can improve upon the executive’s choices – will often be
met. First, if agencies may hold motivations or face incentives that distort the optimal
approach to information disclosure, courts suffer from deficits of expertise and
policymaking ability that hamper their efforts to make things better. Here a serious
problem is that courts decide one case at a time. While this practice has many benefits,74
it makes it difficult for courts to gain a systemic view75 across an array of cases in order
to decide whether an agencies’ decisions are systematically distorted, or to evaluate
whether inter-executive externalities are occurring.
Second, suppose that the court does know (better than the executive) how and
when to disclose information in order to rebut a conspiracy theory. The problem is that
the court may be legally constrained not to act optimally in any event. There is no
necessary connection between the timing of the lawsuit and the optimal timing of
disclosure for addressing the relevant conspiracy theory. In the Judicial Watch case, the
optimal time of disclosure may have been never, given the low benefits; it may also have
been at some time in the future. The court, however, is legally constrained from acting
on its open-ended assessment. It may decide that the plaintiff prevails and disclosure
occurs, or not, but in general it may not fine-tune the timing of disclosure at will.
In all of these remarks, we have made two assumptions that cabin the analysis; we
are not offering a general account of FOIA litigation. We have assumed first of all that –
as in the Judicial Watch litigation – the plaintiff’s avowed purpose is to force a disclosure
that in the plaintiff’s judgment will rebut a spreading conspiracy theory. In internal legal
terms, this is irrelevant; the Supreme Court has repeatedly stated that reviewing courts
should not consider the specific interests of the requester in obtaining FOIA disclosure.76
77 See, e.g., Ctr. for Nat’l Sec. Studies v. U.S. Dep’t of Justice, 331 F.3d 918, 928-29 (D.C. Cir. 2003).
78 See, e.g., DANIEL PIPES, THE HIDDEN HAND: MIDDLE EAST FEARS OF CONSPIRACY 287- 383 (1996).
79 Marvin Zonis & Craig M. Joseph, Conspiracy Thinking in the Middle East, 15 POL. PSYCHOL. 443, 445
80 Cf. Krueger, supra note 10.
However, it is certainly relevant from an external standpoint, where the question is how
to assess the institutional capacities of relevant actors. Where the aim of all concerned
actors, including the plaintiffs, is to supply an optimal response to conspiracy theories
rather than to assert other interests, there are special grounds for doubting that the
litigation process can improve upon executive branch choices.
We have also assumed that the relevant statutes are sufficiently ambiguous or
vague that both agencies and courts are at least in part making policy choices, rather than
enforcing the law in any simple sense. Where this is not so, and the commands of FOIA
are clear, courts should enforce them. If the resulting disclosure is not optimally timed,
the problem lies with the statute (as applied). In general, however, this is not the
situation such cases will pose. Rather the agency resists disclosure under a vague or
broadly worded FOIA exemption, and perhaps also by invoking principles such as the
“mosaic theory,”77 according to which government may resist disclosures that are
innocuous in themselves but that can be assembled into a larger picture damaging to
national security. If the reviewing court does not face a clear legal command, and if the
court lacks confidence (as we do) that the litigation process will on average produce
better responses to conspiracy theorizing, then the court should stay its hand.
D. A Note on Conspiracy Theories Abroad
Our focus has been on domestic conspiracy theories, although some of the
relevant considerations are constant across both domestic and foreign audiences.
Conspiracy theories flourish in many Middle Eastern and predominantly Muslim
countries, so much so that there is a small literature asking why Muslims are so prone to
conspiracy theorizing.78 (One paper by Freudian psychologists even ascribes this “fact”
to Muslim child-rearing practices79; we are skeptical.) If many Muslims abroad are
prone to conspiracy theorizing, so too are many non-Muslims in the United States, as the
evidence given above demonstrates. On the other hand, we have conjectured that there is
a causal link between the prevalence of conspiracy theories and the relative absence of
civil liberties and a well-functioning marketplace of ideas,80 so it is unsurprising that
such theories are even more widespread in the Muslim world than in the United States.
Overall, conspiracy theorizing is undoubtedly virulent in the Muslim world, has a sharply
anti-American inflection, and poses problems that are somewhat distinctive, so a brief
discussion is warranted.
On the diagnostic side, it is highly likely that the virulence of conspiracy
theorizing in Muslim nations has a great deal to do with social cascades and group
polarization, and with weak civil liberties and the lack of a robust market for ideas in
many of those nations. In terms of our suggested policy responses, the foreign setting is
both a worse and a better environment for the U.S. government. It is worse in that the
nature of the relevant institutions and audiences in the Muslim world sharpens many of
the dilemmas and tradeoffs we have described. Typically, the audience is antecedently
skeptical, in the extreme, of anything said by United States officials; shortly we will see
81 Justin Rood, U.S. Government Gave Airtime to Terrorists, Official Admits, ABC NEWS, May 22, 2007,
82 Lynne Duke, The Word at War; Propaganda? Nah, Here’s the Scoop, Say the Guys Who Planted Stories
in Iraqi Papers, WASH. POST, Mar. 26, 2006, at D01.
that this creates enormous pressure for the U.S. to engage in various forms of covert or
anonymous speech. The marketplace of ideas, in many Muslim nations, is institutionally
fragile or dominated by powerful governments. Civil liberties, including free speech, are
often shaky. The upside to the foreign setting, however, is that on some dimensions the
U.S. enjoys greater freedom of action, in part because domestic U.S. politics will tolerate
some actions abroad that it would not tolerate if taken at home.
We begin with the difficulties. The foreign setting sharpens one of the central
tradeoffs we have identified: to enhance the credibility of speech that debunks conspiracy
theories, the government must surrender some degree of control over the institutions of
speech. In 2004, the U.S. government set up a broadcast network for the Middle East –
Al-Hurrah, “the Free One” – that puts out news and third-party opinion. In May 2007, a
House subcommittee called a hearing to investigate reports that Al-Hurrah had broadcast
“terrorist” content, including “a 68-minute call to arms against Israelis by a senior figure
of the terrorist group Hezbollah; [and] deferential coverage of Iranian President
Mahmoud Ahmadinejad’s Holocaust denial conference . . . ”.81 Legislators sharply
questioned officials of the Broadcasting Board of Governors, the government corporation
that ultimately funds Al-Hurrah, and those officials had to promise to address the
legislators’ concerns. Those problems, however, were part and parcel of a broader
strategy for enhancing credibility by permitting other viewpoints and voices on the air.
In general, in order to enhance its credibility with antecedently skeptical Muslim
audiences, the U.S. government must go a long way towards surrendering control over
the content of its speech (or must speak anonymously, a strategy that carries its own
risks, as we mention next). However, as this episode reveals, domestic political
constraints may preclude whatever mix of credibility and control is optimal from the
standpoint of dampening conspiracy theories or promoting U.S. public relations goals
The alternative to surrendering control over the content of the government’s
responses, in order to enhance credibility, is for government officials or agents to speak
anonymously. A mini-scandal erupted in 2006 when U.S. newspapers revealed that the
Lincoln Group, an independent contractor of “influence services,” had paid Iraqi
newspapers to publish hundreds of “news stories” written by U.S. military personnel but
not identified as such, most of which portrayed events in Iraq in cheery terms or rebutted
circulating conspiracy theories.82 The stories were factually true, but selective. As
against the obvious moral objections to this practice, the Lincoln Group argued that
speech identified as stemming from U.S. sources would, even if true, credible and
important, be utterly discounted by the Iraqi audience, leaving the field entirely to
conspiratorial and hostile rumors. On this view the implicit lie of planting “news” stories
not identified to their true sources is necessary, in a deliberative environment that is
already warped, to the goal of putting all relevant information before a quasi-rational
audience. Where the marketplace of ideas is already malfunctioning, in the sense that
relevant audiences discount to zero statements that should carry positive weight, practices
84 Editorial, Hearts, Minds and Padlocks, N.Y. TIMES, Mar. 30, 2004, at A20.
86 Roula Khalaf, US Takes An Optimistic View in Battle for Hearts and Minds in the Arab World: The New
American-sponsored al-Hurra Channel Aims to Reach Young People With Help From Some Good-News
Stories, FIN. TIMES, Jan. 15, 2004, at 11.
that would not be permissible in a well-developed liberal state might be permissible on
A better objection to this practice may instead be tactical. By outsourcing this
form of quasi-propaganda to an independent contractor whose participation would sooner
or later be brought to light, the U.S. government fell between two stools, obtaining
neither the credibility benefits of full transparency nor the credibility benefits of totally
anonymous speech. Reuel Marc Gerecht, a former CIA case officer, commented that
“[t]he historical parallel would be the [CIA’s] efforts during the Cold War to fund
magazines, newspapers and journalists who believed that the West should triumph over
communism. Much of what you do ought to be covert, and, certainly, if you contract it
out, it isn’t.”83
So far we have discussed the distinctive difficulties of the foreign setting. On
other dimensions, however, the foreign setting loosens various legal and political
constraints, allowing the U.S. government greater freedom in responding to conspiracy
theories. In 2004, the U.S. administrator for Iraq, L. Paul Bremer, ordered troops to shut
down a weekly newspaper in Baghdad that had propounded false conspiracy theories
damaging to the U.S., such as a story that “an American missile, not a terrorist car bomb,
had caused an explosion that killed more than 50 Iraqi police recruits.”84 Whether this
sort of action does more harm than good, in similar environments, is a complicated
question, depending on difficult judgments about the etiology of conspiracy theories, the
consequences of censorship, and the efficacy of U.S. counterspeech. On the one hand,
there are the familiar arguments that censorship attracts attention to the censored speech
or publication and fuels further conspiracy theorizing; perhaps, the inference might run,
the U.S. is moving against a particular rumor because it is true, or is moving against a
particular paper because it is exposing actual U.S. conspiracies. Furthermore, censorship
might just drive the conspiracy theories underground, to be spread and mutated by
personal rumor-mongering that is less susceptible to focused rebuttal.
On the other hand, the peculiar environment in which Bremer acted may weigh in
favor of a policy of censoring publication of conspiracy theories. One editorial argued
that “[t]he occupation authorities have plenty of means, including their own television
station, to get out a more favorable message.”85 However, this ignores the effect
discussed above, that the antecedent skepticism of the Iraqi audience is so strong that any
U.S. statements, even if true, credible and important, will be ignored altogether. With an
audience already thoroughly in the grip of conspiracy theories, open counterspeech may
simply be more grist for the conspiratorial mill. Consider that when Al-Hurra began its
operations, a conspiracy theory quickly circulated, claiming that the short-term contracts
given to Al-Hurra personnel showed that the station was set up only to bolster George W.
Bush’s reelection campaign, and would presumably be shut down after the election.86
Given the extremely low efficacy of U.S. counterspeech in this sort of environment, the
realistic options may be limited to censorship and anonymous or quasi-anonymous
counterspeech in the style of the Lincoln Group. Whatever the merits of these pragmatic
and tactical questions, the availability of censorship gives U.S. officials operating in
foreign countries an extra instrument for coping with conspiracy theories, one that is not
available in the domestic arena due to both legal and political constraints.
Our goal here has been to understand the sources of conspiracy theories and to
examine potential government responses. Most people lack direct or personal information
about the explanations for terrible events, and they are often tempted to attribute such
events to some nefarious actor. The temptation is least likely to be resisted if others are
making the same attributions. Conspiracy cascades arise through the same processes that
fuel many kinds of social errors. What makes such cascades most distinctive, and
relevantly different from other cascades involving beliefs that are both false and harmful,
is their self-insulating quality. The very statements and facts that might dissolve
conspiracy cascades can be taken as further evidence on their behalf. These points make
it especially difficult for outsiders, including governments, to debunk them.
Some conspiracy theories create serious risks. They do not merely undermine
democratic debate; in extreme cases, they create or fuel violence. If government can
dispel such theories, it should do so. One problem is that its efforts might be
counterproductive, because efforts to rebut conspiracy theories also legitimate them. We
have suggested, however, that government can minimize this effect by rebutting more
rather than fewer theories, by enlisting independent groups to supply rebuttals, and by
cognitive infiltration designed to break up the crippled epistemology of conspiracyminded
groups and informationally isolated social networks.
This paper can be downloaded free of charge from the Social Science Research Network at:
Harvard University Law School
Public Law & Legal Theory Research Paper Series
University of Chicago Law School
Public Law & Legal Theory Research Paper Series
Paper No. 199
University of Chicago Law School
Law & Economics Research Paper Series
Paper No. 387
CASS R. SUNSTEIN
University of Chicago – Law School
Harvard University – Harvard Law School
This paper can be downloaded free of charge from the
Social Science Research Network at:
Electronic copy available at: http://ssrn.com/abstract=1084585
Preliminary draft 1/15/08
All rights reserved
Cass R. Sunstein*
AbstractPreliminary draft 1/15/08
All rights reserved
Cass R. Sunstein*
Many millions of people hold conspiracy theories; they believe that powerful
people have worked together in order to withhold the truth about some important
practice or some terrible event. A recent example is the belief, widespread in some parts
of the world, that the attacks of 9/11 were carried out not by Al Qaeda, but by Israel or
the United States. Those who subscribe to conspiracy theories may create serious risks,
including risks of violence, and the existence of such theories raises significant
challenges for policy and law. The first challenge is to understand the mechanisms by
which conspiracy theories prosper; the second challenge is to understand how such
theories might be undermined. Such theories typically spread as a result of identifiable cognitive blunders, operating in conjunction with informational and reputational influences. A distinctive feature of conspiracy theories is their self-sealing quality.
Conspiracy theorists are not likely to be persuaded by an attempt to dispel their theories;
they may even characterize that very attempt as further proof of the conspiracy. Because
those who hold conspiracy theories typically suffer from a “crippled epistemology,” in
accordance with which it is rational to hold such theories, the best response consists in
cognitive infiltration of extremist groups. Various policy dilemmas, such as the question
whether it is better for government to rebut conspiracy theories or to ignore them, are
explored in this light.
“The truth is out there”:1 conspiracy theories are all around us. In August 2004, a
poll by Zogby International showed that 49 percent of New York City residents, with a
* Karl N. Llewellyn Distinguished Service Professor of Jurisprudence, University of Chicago.
** Professor of Law, Harvard Law School. Thanks to Mark Tushnet for helpful conversations, to Eric
Posner and Andrei Shleifer for valuable comments, and to Elisabeth Theodore for excellent research assistance.
1 This slogan was popularized by the television show The X-Files, see http://en.wikipedia.org/wiki/The_XFiles.
9/11 conspiracy theorists often call themselves the 9/11 Truth Movement. See The 9/11 Truth
Movement, http://www.911truth.org (last visited Nov. 14, 2007).
10 See Alan Krueger, WHAT MAKES A TERRORIST? 75-82 (2007). Krueger believes that low civil liberties cause terrorism, but acknowledges that his data are also consistent with the hypothesis that terrorism causes governments to reduce civil liberties. See id. at 148. Of course, the two effects may both occur, in a mutually reinforcing pattern. Following Krueger, we assume that low civil liberties tend to produce terrorism, a hypothesis that is supported by the mechanisms we adduce.
margin of error of 3.5 percent, believed that officials of the U.S. government “knew in
advance that attacks were planned on or around September 11, 2001, and that they
consciously failed to act.”2 In a Scripps-Howard Poll in 2006, with an error margin of 4
percent, some 36 percent of respondents assented to the claim that “federal officials either
participated in the attacks on the World Trade Center or took no action to stop them.”3
Sixteen percent said that it was either very likely or somewhat likely that “the collapse of
the twin towers in New York was aided by explosives secretly planted in the two
2 Zogby International, Half of New Yorkers Believe US Leaders Had Foreknowledge of Impending 9-11
Attacks and “Consciously Failed” To Act, Aug. 30, 2004, http://zogby.com/news/ReadNews.dbm?ID=855.
3 Thomas Hargrove & Guido H. Stempel III, A Third of U.S. Public Believes 9/11 Conspiracy Theory,
SCRIPPS HOWARD NEWS SERVICE, Aug. 2, 2006,
5 One in 5 Canadians Sees 9/11 as U.S. Plot – Poll, REUTERS, Sept. 11, 2006.
6 Matthew A. Gentzkow & Jesse M. Shapiro, Media, Education and Anti-Americanism in the Muslim
World, 18 J. ECON. PERSPECTIVES 117, 117 (2004)
7 Id. at 120.
8 See, e.g., CONSPIRACY THEORIES: THE PHILOSOPHICAL DEBATE (David Coady ed., 2006); CHANGING
CONCEPTIONS OF CONSPIRACY (Carl F. Graumann & Serge Moscovici eds., 1988).
9 There is also a body of work that collects many interesting examples of conspiracy theories, but without
any sustained analytic approach. See, e.g., Michael Barkun, A CULTURE OF CONSPIRACY (2003); Daniel
Pipes, CONSPIRACY (1997). For a treatment of conspiracy theories from the standpoint of cultural studies,
see Mark Fenster, CONSPIRACY THEORIES (1999).
I. Definitions and Mechanisms
11 See note 8 supra.
12 See Mark Lane, PLAUSIBLE DENIAL: WAS THE CIA INVOLVED IN THE ASSASSINATION OF JFK? (1991)
(arguing that it was); Alan Cantwell, AIDS AND THE DOCTORS OF DEATH: AN INQUIRY INTO THE ORIGINS
OF THE AIDS EPIDEMIC (1988) (suggesting AIDS was the product of a biowarfare program targeting gay people); Don Phillips, Missile Theory Haunts TWA Investigation; Despite Lack of Evidence and Officials’
Denials, Some Insist Friendly Fire Caused Crash, WASH. POST, Mar. 14, 1997, at A03; 149 CONG. REC. S10022 (daily ed. July 28, 2003) (statement of Sen. Inhofe) (“With all the hysteria, all the fear, all the
phony science, could it be that manmade global warming is the greatest hoax ever perpetrated on the
American people? I believe it is.”); David Mills, Beware the Trilateral Commission!; The Influential World
Panel Conspiracy Theorists Love to Hate, WASH. POST, Apr. 25, 1992, at H1 (describing various
conspiracy theories about the Commission); William F. Pepper, AN ACT OF STATE: THE EXECUTION OF
MARTIN LUTHER KING (2003) (arguing that the military, the CIA, and others within the government
conspired to kill King); Kevin Diaz, Findings Don’t Slow Conspiracy Theories on Wellstone Crash; An
Official Investigation Has Focused on Pilot Error and Weather. Some Observers Still Have Suggested a
Political Plot., STAR TRIBUNE (Minn.), June 3, 2003, at A1; Patty Reinert, Apollo Shrugged: Hoax Theories
About Moon Landings Persist, HOUSTON CHRON., Nov. 17, 2002, at A1.
13 See Bob Woodward & Carl Bernstein, ALL THE PRESIDENT’S MEN (1974); George Lardner Jr. & John
Jacobs, Lengthy Mind-Control Research by CIA Is Detailed, WASH. POST, Aug. 3, 1977, at A1;
Memorandum from L. L. Lemnitzer, Chairman, Joint Chiefs of Staff, to the Secretary of Defense,
Justification for U.S. Military Intervention in Cuba (Mar. 13, 1962), available at
15 See Karl R. Popper, The Conspiracy Theory of Society, in CONSPIRACY THEORIES, supra note 8; see also
KARL R. POPPER, THE OPEN SOCIETY AND ITS ENEMIES, VOL. 2 (1966).
17 See NASSIM TALEB, FOOLED BY RANDOMNESS (2001).
18 An illuminating discussion is Edna Ullmann-Margalit, The Invisible Hand and the Cunning of Reason, 64 SOC.
RES. 181 (1997).
19 See Taleb, supra note.
20 See, e.g., James Risen & Eric Lichtblau, Bush Lets U.S. Spy on Callers Without Courts, N.Y. TIMES, Dec.
16, 2005, at A1; Jane Mayer, The Black Sites: A Rare Look Inside the C.I.A.’s Secret Interrogation
Program, THE NEW YORKER, Aug. 13, 2007, at 46.
21 Consider here Amartya Sen’s finding that in the history of the world, no famine has occurred in a nation with a free press and democratic elections. See Amartya Sen, Poverty and Famines (1983). Of course it would be excessive to infer that in authoritarian nations, famines are a “conspiracy” of the authoritarians.
22 Brian L. Keeley, Of Conspiracy Theories, in CONSPIRACY THEORIES, supra note 8, at 46, 56-57.
23 Quoted in id. at 57.
24 Imre Lakatos, Falsification and Methodology of Scientific Research Programmes, in CRITICISM AND THE
GROWTH OF KNOWLEDGE 91 (Imre Lakatos & Alan Musgrave eds., 1970); see Steve Clarke, Conspiracy
Theories and Conspiracy Theorizing, in CONSPIRACY THEORIES, supra note 8, at 78.
25 See Diana G. Tumminia, WHEN PROPHECY NEVER FAILS: MYTH AND REALITY IN A FLYING-SAUCER
26 Keeley, supra note 22, at 55-56.
27 See Richard Hofstader, The Paranoid Style in American Politics, in THE PARANOID STYLE IN AMERICAN
POLITICS AND OTHER ESSAYS (1979); Robert S. Robins & Jerrold M. Post, POLITICAL PARANOIA (1997).
See, e.g., Deiter
Groh, The Temptation of Conspiracy Theory, in CHANGING CONCEPTIONS OF CONSPIRACY, supra note 8, at
1. Our suggestion is that the lens of psychopathology is not helpful, whether it is interpreted in individual
or collective terms.
28 See Erich Wulff, Paranoic Conspiratory Delusion, in CHANGING CONCEPTIONS OF CONSPIRACY, supra
note 8, at 172.
29 There is an immense and growing literature on this question. For examples, with relevant citations, see
Glaeser, supra; Sendhil Mullainathan and Andrei Shleifer, The Market for News, 95 AM. ECON. REV. 1031
(2005); Sendhil Mullainathan and Andrei Shleifer, Media Bias (2002), available at
http://www.nber.org/papers/w9295.pdf; Edward Glaeser and Cass R. Sunstein, Extremism and Social
Learning, J. LEGAL ANALYSIS (forthcoming 2008).
30 Russell Hardin, The Crippled Epistemology of Extremism, in POLITICAL RATIONALITY AND EXTREMISM
3, 16 (Albert Breton et al. eds., 2002).
31 Id. Of course it is also true that many extremists have become extreme, or stayed extreme, after being
exposed to a great deal of information on various sides.
32 See KRUEGER, supra note 10, at 75-82.
33 See id. at 89-90.