We may earn a commission from links on this page.For April Fools' Day, I thought I'd look into the fascinating story of a major source of one of the longest-lasting and widely believed conspiracy theories in American history. According to a 2023 YouGov poll, 54% of Americans believe that Lee Harvey Oswald did not act alone when he gunned down president John F. Kennedy in 1963so most Americans are wrong about this, and they're wrong about it partly due to a work of fiction published in the late 1960s.The granddaddy of all modern conspiracy theoriesWidespread disbelief in the "official story" of the Kennedy assassination has inspired a library of books, congressional hearings, major motion pictures, and most recently, the declassification of thousands of documents (none of which, by the way, support the idea of a conspiracy). But more importantly, Kennedy assassination conspiracies normalized and mainstreamed conspiracy theories in general, bolstering every piece of fake news that followed, from Obama's birth certificate to vaccine skepticismif the government could cover up a political assassination, the argument goes, they could be up to anything. But what if the basis of the most widely accepted Kennedy conspiracy theory was a work of satirical fiction? That's the premise behind Phil Tinline's recent book Ghosts of Iron Mountain: The Hoax of the Century, Its Enduring Impact, and What It Reveals About America Today, an examination of the history and impact of Report from Iron Mountain, a 1967 work of fiction that started as left-wing satire but became one of the most influential texts in American history. Oliver Stone's JFK and the "CIA did it" conspiracyWhile there are hundreds of theories about who was really behind Kennedy's assassination and why they did it, probably the most widely accepted version of the story, the one you may believe, is the theory Oliver Stone went with in his 1991 film JFK: The CIA killed Kennedy because he was about to withdraw troops from Vietnam and end the Cold War. Main character Jim Garrison lays it out like this in the film: "What took place on November 22, 1963 was a coup d'tat ... The war is the biggest business in America worth $80 billion a year. President Kennedy was murdered by a conspiracy that was planned and advanced at the highest levels of our government, and was carried out by fanatical and disciplined cold warriors in the Pentagon and CIA's covert-operation apparatus."But where did Stone's protagonist get this idea? As Tinline's book details, the CIA theory is laid out in JFK by "X," a character based on real-life former air-force colonel L. Fletcher Prouty. Prouty's source is what he believed was a "suppressed think-tank paper" called Report from Iron Mountain: On the Possibility and Desirability of Peace. And Report from Iron Mountain is a literary hoax dreamed up by the editors of the short-lived, left-wing satirical journal The Monocle. The birth of Report from Iron MountainBack in 1966, Victor Navasky, editor of The Monocle, read a news item about a dip in the stock market caused by a cutback in military spending; Wall Street called it a"peace scare." This inspired Navasky to commission writer Leonard Lewin, with help from economist John Kenneth Galbraith and others, to write Report from Iron Mountain, supposedly the leaked findings of "Special Study Group" tasked by the Kennedy Administration to plan the transition from a wartime to a peacetime economy. Its conclusion: Peace would likely bring about the collapse of the USA.Iron Mountain was edited by H.L. Mencken, and published as a work of non-fiction in 1967, but most reviewers and literary types recognized it as social commentary. Members of the general public were divided, however, so author Lewin dispelled all doubt by confirming Iron Mountain was a hoax in 1974. And that should have been the end of it. But it wasn't.The strange afterlife of Report from Iron MountainThe real point of Iron Mountain was to highlight the absurdity of the Cold War through exaggeration and satirethe book tips its hand fairly heavily by suggesting UFO hoaxes, "blood games," and bringing back slavery as possible replacement for warbut its ideas, shorn of their satirical context, spun outside the control of the literary types who dreamed it up. Iron Mountain started percolating in the poisonous coffee pot of fringe thinkers, combining and metastasizing with other seminal, fictional, conspiracy texts like Alternative 3 and The Protocols of the Brotherhood of Zion, until Iron Mountain became a foundational text for cranks, part of the ideological framework they can hang anything on. It wasn't just Oliver Stone's source who mistook Report from Iron Mountain as truth. Much to the author's dismay, the book was also rediscovered by the burgeoning-right wing militia movement of the 1980s, and reprinted as non-fiction by the anti-semitic Noontide Press. Milton William Cooper excerpted Iron Mountain in seminal conspiracy theory text Behold a Pale Horse, said to be a favorite of Oklahoma City Bomber Timothy McVeigh. From there, it's a straight shot to "The Deep State," Q-anon, Alex Jones, Covid cover-ups, and whatever else loonies are on about this week on X.