The 9/11 attacks catalyzed a tremendous shift in American foreign policy in the Middle East. Rather than prioritizing petrol, Washington targeted terrorist organizations, dethroned a dictator, and lobbied throughout the region for liberalization. Yet despite the billions of dollars spent policing Baghdad and protecting Benghazi, the unpopularity of the United States in the Arab world continues to be fueled by the belief that Islamist terrorists had nothing to do with 9/11, with many claiming the attacks were an American, Israeli, or joint American-Israeli conspiracy. In this sense, overcoming 9/11 revisionism is, perhaps, the greatest challenge facing American public diplomacy in the coming decade: So long as such conspiracy theories persist, Arabs will continue to view American policies aimed at preventing “another 9/11” as thoroughly illegitimate since, as they see it, 9/11 is just a big American lie.

In a report on Muslim-Western relations released on July 21 of this year, the Pew Research Center asked Muslim respondents in eight countries—including Lebanon, Jordan, Egypt, Turkey, and Pakistan—whether they thought groups of Arabs carried out the 9/11 attacks on the United States. In every country, less than 30 percent of respondents professed their belief for the idea, and in Jordan, Egypt, and Turkey the level of acceptance is lower today than it was in 2006. Indeed, the same revolutionary Arab Street that toppled Mubarak in Egypt also registered the highest level of denial among all the countries surveyed, with a full 75 percent of respondents recording their disbelief.

Pew’s poll numbers from Egypt track closely with my own experience in the country, where I lived and conducted doctoral research during parts of its tumultuous spring. Perhaps unsurprisingly, I found that 9/ll revisionism was particularly prominent among Islamists, for whom rewriting history is necessary for deflecting the accusation that their ideology motivates mass murder. “There is no Al Qaeda,” former Muslim Brotherhood Supreme Guide Mehdi Akef told me in complete seriousness. “It’s an American expression. It’s just an ideology, Al Qaeda. This ideology comes from America and their coalitions.” In Akef’s inversion of reality, 9/11 constituted an American attack on the Middle East, followed by an Islamist policy of self-defense. “When they fight in Iraq and Afghanistan, Al Qaeda thinks it’s a jihad because the fight is against occupation,” he said. “And it is jihad to fight occupation. And when Americans kill civilians everywhere, it’s a big crime against humanity.”

Younger generations of Muslim Brothers echo Akef’s distortions without fail. “America did [9/11] for some business interests,” Alexandria Brotherhood leader Ali Abdelfattah said to me. Abdel Monem Abouel Fetouh, a former Brotherhood leader whom The New York Times touts as a “liberal Islamist,” agrees: “I don’t believe it was jihadists—it was too big an operation,” he told me. “This was done by a country, not individuals. It’s not a conspiracy theory—it’s just logical. They didn’t bring crimes before the U.S. justice system until now. Why? Because it’s part of the conspiracy.” Even Islam Lotfy, who recently left the Brotherhood to establish his own political party and works as a contractor for USAID in Egypt, finds American complicity in 9/11 plausible. “I can’t imagine someone flying for twenty minutes and nobody realizes it, and then another plane goes and crashes and then another in Pennsylvania,” he said. Sobhi Saleh, a former parliamentarian who is considered among the Brotherhood’s top legal thinkers, had a slightly different theory. “The Jews and the Zionist lobby [did it],” he said, referencing a book that a Lebanese Christian cleric gave him. “And this study is well known in America and it’s on the Internet. … It was a scientific research.”

Yet Islamists were hardly the only group I encountered in Egyptian society that denied Al Qaeda’s complicity in 9/11. Revolutionary socialists, who comprise an important segment of the youth activists that catalyzed the January anti-Mubarak revolt, see the machinations of global domination at work. “Personally, I think the imperial interests needed something like this,” Mustafa Shawqi, a leader in the Coalition of Revolutionary Youth, told me. “Gas tycoons—blocking any attempt for democratic change in the Arab world and serving the security of Israel.” And a number of self-proclaimed liberals sounded awfully like the Islamists when asked who was responsible for 9/11. “The CIA knows who did it. I don’t know,” said liberal Wafd party youth activist Mohamed Fouad. “It will remain a question mark. Al Qaeda is part of the theories, but it was organized with others. And let’s not forget that Al Qaeda is made and supported by the Americans.”