Oppenheimer's lack of candor with the FBI and Army counter intelligence is deeply troubling and an indication of conflicted and unreliable loyalty. I believe that his security clearance was revoked for good cause.
I agree.
The movie doesn’t handle all this as well as it might have, but Leslie Groves’/Matt Damon’s remark towards the end is important. He is asked by the review board deciding on Oppenheimer’s clearance whether, in retrospect, he thinks Oppenheimer should have gotten a security clearance in the first place. He answers that — in retrospect — he wouldn’t have cleared “any of them,” meaning that the whole project was so riddled with security risks that in anything other than an extreme wartime crisis situation, a LOT of people shouldn’t have been cleared.
Too much of this is left in the shadows in the movie, and in the histories of the period, which tend to focus too narrowly on the Oppenheimer case (and sometimes Klaus Fuchs and David Greenglass). It would be interesting to know, for example, how many people were considered for the Manhattan Project and refused a clearance. That would put Oppenheimer’s case in better context.
My open question has for years been David Greenglass. How the heck did he get assigned to Los Alamos, given that Julius Rosenberg was already running a significant Soviet industrial espionage ring, and given that Greenglass’ personal history was also highly problematic? I’ve always wondered if Greenglass was placed, and if so, by whom. Klaus Fuchs at least had scientific expertise that could plausibly have led investigators to give him the benefit of the doubt. But Greenglass was a machinist — a highly skilled one, I’m sure, but still ... — and his background, along with his sister and BIL’s, should have triggered a closer look. Were security really that sloppy, or was Greenglass placed?