In 2010, Marc Estrin, a novelist and far-left activist from Vermont, found an online version of a paper by Cass Sunstein, a professor at Harvard Law School and the most frequently cited legal scholar in the world. The paper, called “Conspiracy Theories,” was first published in 2008, in a small academic journal called the Journal of Political Philosophy. In it, Sunstein and his Harvard colleague Adrian Vermeule attempted to explain how conspiracy theories spread, especially online. At one point, they made a radical proposal: “Our main policy claim here is that government should engage in cognitive infiltration of the groups that produce conspiracy theories.” The authors’ primary example of a conspiracy theory was the belief that 9/11 was an inside job; they defined “cognitive infiltration” as a program “whereby government agents or their allies (acting either virtually or in real space, and either openly or anonymously) will undermine the crippled epistemology of believers by planting doubts about the theories and stylized facts that circulate within such groups.” View more Nowhere in the final version of the paper did Sunstein and Vermeule state the obvious fact that a government ban on conspiracy theories would be unconstitutional and possibly dangerous. (In a draft that was posted online, which remains more widely read, they emphasized that censorship is “inconsistent with principles of freedom of expression,” although they “could imagine circumstances in which a conspiracy theory became so pervasive, and so dangerous, that censorship would be thinkable.”)* “I was interested in the mechanisms by which information, whether true or false, gets passed along and amplified,” Sunstein told me recently. “I wanted to know how extremists come to believe the warped things they believe, and, to a lesser extent, what might be done to interrupt their radicalization. But I suppose my writing wasn’t very clear.” Sunstein has studied the spread of information since the mid-nineties, when he co-wrote a series of law-review articles about “cascade theory”—a model describing how opinions travel across juries, markets, and subcultures. He was particularly interested in what he called the Law of Group Polarization: how ideologically homogenous groups can become “breeding grounds for unjustified extremism, even fanaticism.” In 2001, his first book on political polarization on the Internet, “Republic.com,” warned that, even when people have access to a range of robust and challenging views, many will favor information that confirms what they already believe. He updated the book in 2007, as “Republic.com 2.0: Revenge of the Blogs,” and again this year, as “#Republic: Divided Democracy in the Age of Social Media.” When he wrote “Republic.com,” social media didn’t really exist; when he wrote “Republic.com 2.0,” social media’s impact was so negligible that he could essentially ignore it; in “#Republic,” he argues that services such as Facebook comprise the contemporary agora, and that their personalized algorithms will make it ever more difficult for Americans to understand their fellow-citizens. In the endless debates about what constitutes “fake news,” we tend to invoke clear cases of unfounded rumor or outright deceit (“Melania has a body double,” or “President Trump saves two cats from drowning after Hurricane Harvey”). More prevalent, and more bewildering, are the ambiguous cases—a subtly altered photograph, an accurate but misleading statistic, a tendentious connection among disparate dots. Between the publication of “Republic.com 2.0” and “#Republic,” Sunstein became a target of the same online rumor mill he’d been studying from a distance, and many of the conspiracy theories about “Conspiracy Theories” fell into this gray area—overheated, but not wholly made up. “If you had told me that this obscure paper would ever become such a publicly visible and objectionable thing, I would have thought it more likely that Martians had just landed in Times Square,” Sunstein said. “In hindsight, though, I suppose it’s sort of appropriate that I got caught up in the mechanisms I was writing about.”

When Barack Obama became President, in 2009, he appointed Sunstein, his friend and former colleague at the University of Chicago Law School, to be the administrator of the Office of Information and Regulatory Affairs. The O.I.R.A. reviews drafts of federal rules, and, using tools such as cost-benefit analysis, recommends ways to make them more efficient. O.I.R.A. administrator is the sort of in-the-weeds post that even lifelong technocrats might find unglamorous; Sunstein had often described it as his “dream job.” He took a break from academia and moved to Washington, D.C. It soon became clear that some of his published views, which he’d thought of as “maybe a bit mischievous, but basically fine, within the context of an academic journal,” could seem far more nefarious in the context of the open Internet. Estrin, who seems to have been the first blogger to notice the “Conspiracy Theories” paper, published a post in January, 2010, under the headline “Got Fascism?” “Put into English, what Sunstein is proposing is government infiltration of groups opposing prevailing policy,” he wrote on the “alternative progressive” Web site the Rag Blog. Three days later, the journalist Daniel Tencer (Twitter bio: “Lover of great narratives in all their forms”) expanded on Estrin’s post, for Raw Story. Two days after that, the civil-libertarian journalist Glenn Greenwald wrote a piece for Salon headlined “Obama Confidant’s Spine-Chilling Proposal.” Greenwald called Sunstein’s paper “truly pernicious,” concluding, “The reason conspiracy theories resonate so much is precisely that people have learned—rationally—to distrust government actions and statements. Sunstein’s proposed covert propaganda scheme is a perfect illustration of why that is.” Sunstein’s “scheme,” as Greenwald put it, wasn’t exactly a government action or statement. Sunstein wasn’t in government when he wrote it, in 2008; he was in the academy, where his job was to invent thought experiments, including provocative ones. But Greenwald was right that not all skepticism is paranoia. Three days after Estrin’s post was published on the Rag Blog, the fire jumped to the other side of the road. Paul Joseph Watson, writing for the libertarian conspiracist outfit InfoWars, linked to Estrin’s post and riffed on it, in a free-associative mode, for fifteen hundred words. “It is a firmly established fact that the military-industrial complex which also owns the corporate media networks in the United States has numerous programs aimed at infiltrating prominent Internet sites and spreading propaganda to counter the truth,” Watson wrote. His boss at InfoWars, Alex Jones, began expanding on this talking point on his daily radio show: “Cass Sunstein says ban conspiracy theories, and that’s whatever he says it is. That’s on record.” At the time, Glenn Beck hosted both a daily TV show on Fox News and a syndicated radio show; according to a Harris poll, he was the country’s second-favorite TV personality, after Oprah Winfrey. Beck had been delivering impassioned rants against Sunstein for months, calling him “the most dangerous man in America.” Now he added the paper about conspiracy theories to his litany of complaints. In one typical TV segment, in April of 2010, he devoted several minutes to a close reading of the paper, which lists five possible ways that a government might respond to conspiracy theories, including banning them outright. “The government should ban them,” Beck said, over-enunciating to express his incredulity. “How a government with an amendment guaranteeing freedom of speech bans a conspiracy theory is absolutely beyond me, but it’s not beyond a great mind and a great thinker like Cass Sunstein.” In another show, Beck insinuated that Sunstein had been inspired by Edward Bernays, the author of a 1928 book called “Propaganda.” “I got a flood of messages that night, saying, ‘You should be ashamed of yourself, you’re a disciple of Bernays,’ ” Sunstein recalled. “The result was that I was led to look up this interesting guy Bernays, whom I might not have heard of otherwise.” For much of 2010 and 2011, Sunstein was such a frequent target on right-wing talk shows that some Tea Party-affiliated members of Congress started to invoke his name as a symbol of government overreach. Earlier in the Obama Administration, Beck had targeted Van Jones, now of CNN, who was then a White House adviser on green jobs. After a few weeks of Beck’s attacks, Jones resigned. “Then Beck made it sort of clear that he wanted me to be next,” Sunstein said. “It wasn’t a pleasant fact, but I didn’t see what I could do about it. So I put it out of my mind.” Sunstein was never asked to resign. He served as the head of O.I.R.A. for three years, then returned to Harvard, in 2012. Two years later, he published an essay collection called “Conspiracy Theories and Other Dangerous Ideas.” The first chapter was a revised version of the “Conspiracy Theories” paper, with several qualifications added and with Vermeule’s name removed. But the revisions did nothing to improve Sunstein’s standing on far-right talk shows, where he had already earned a place, along with Saul Alinsky and George Soros and Al Gore, in the pantheon of globalist bogeymen. Beck referred to Sunstein as recently as last year, on his radio show, while discussing the Obama Administration’s “propaganda” in favor of the Iran nuclear deal. “We no longer have Jefferson and Madison leading us,” Beck said. “We have Saul Alinsky and Cass Sunstein. Whatever it takes to win, you do.” Last December, Alex Jones—who is, improbably, now taken more seriously than Beck by many conservatives, including some in the White House—railed against a recent law, the Countering Foreign Propaganda and Disinformation Act, claiming, speciously, that it would “completely federalize all communications in the United States” and “put the C.I.A. in control of media.” According to Jones, blame for the law rested neither with the members of Congress who wrote it nor with President Obama, who signed it. “I was sitting here this morning . . . And I keep thinking, What are you looking at that’s triggered a memory here?” Jones said. “And then I remembered, Oh, my gosh! It’s Cass Sunstein.”