The most disturbing thing about this film is not that it's a load of hogwash (the CPUSA was never really as much an espionage threat as the movie makes out). The troubling aspect is the way that it whitewashes the wholly unsavory tactics of the FBI and the UnAmerican Activities Committee. Secret informants, gossip turned into accusations, warrantless searches - these are the kind of things secret police thugs like the KGB did, and presumably, what the good patriotic Americans were fighting. Yet the FBI did them and didn't bat an eye. That's the only realistic part of this movie, and they present it with no sense of shame at all. Add to this undermining the Constitution itself by having only Communists invoke the Bill of Rights. The film also makes thinly veiled accusations that the black civil rights movement was communist-inspired, another pack of lies. It's extremely difficult in this day to excuse such outrageous propaganda, even understanding the paranoia of the times, when one realizes how damaging it was to real people then.