The New York Times reports that beginning in 1945, the FBI began spying on the French philosophers, fearing that their ideas on being and nothingness were part of a plot against the United States:
[Sartre and Camus]’s lectures at Columbia University were well attended by students and faculty members — and by agents from J. Edgar Hoover’s F.B.I.
Yet Sartre, on his visit, was actually invited to the Pentagon; Camus, in contrast, “was stopped at immigration…Hoover sent out a ‘stop letter’ to all U.S. customs agents saying this man should be detained,” Mr. Martin said. Eventually, Camus was allowed to proceed to New York, where his novel “L’Étranger” (“The Stranger”) had just been published in English.
“Hoover thought there must be some kind of conspiracy between communists, blacks, poets and French philosophers. He was hoping for some kind of evidence of conspiracy,” he said.
The F.B.I. was baffled by Sartre. “These agents were trying to work out what the hell existentialism was all about,” said Mr. Martin, adding that “20 years later there’s a note in Sartre’s file saying ‘I can’t work out if he’s pro-Communist or anti-Communist.’ They were still baffled!”
“Camus had been a member of the French Communist party, but the F.B.I. didn’t seem to know that,” said Mr. Martin. “The thing that disturbed them was that he was a member of the resistance.”