Imposing or propping up dictators subservient to the U.S. has long been, and continues to be, the preferred means for U.S. policymakers to ensure tha… - Glenn Greenwald

There's a very similar and at least equally important (though far less discussed) constituency deeply vested in the perpetuation of this fear. It's the sham industry... "terrorism experts," who have built their careers on fear-mongering... and can stay relevant only if that threat does. These "terrorism experts" form an incredibly incestuous, mutually admiring little clique in and around Washington. They're employed at think tanks, academic institutions, and media outlets. They can and do have mildly different political ideologies -- some are more Republican, some are more Democratic -- but, as usual for D.C. cliques, ostensible differences in political views are totally inconsequential when placed next to their common group identity and career interest: namely, sustaining the myth of the Grave Threat... in order to justify their fear-based careers, the relevance of their circle, and their alleged "expertise." Like all adolescent, insular cliques, they defend one another reflexively whenever a fellow member is attacked, closing ranks with astonishing speed and loyalty; they take substantive criticisms very personally as attacks on their "friends," because a criticism of the genre and any member in good standing of this fiefdom is a threat...

Bush DOJ lawyer Jack Goldsmith hailed what he called "an underappreciated phenomenon: the patriotism of the American press". [...] The revolvind door moves the media figures into high-level Washington jobs, jut as government officials often leave office to the reward of a lucrative media contract.

Over the pasty decades, the fear of terrorism—stoked by consistent exaggerations of the actual threat—has been exploited by US leaders to justify a weird array of extremist policies.