The McCarthyism allegory was never necessary to induce fear. It worked in the first place because assimilation and ostracization are a natural human phenomenon in any culture. Invasion of the Body Snatchers is a good movie that avoids becoming a great one by ignoring the unique venues promised by its own concept. The tense hot-seat scenes of suspicion and hysteria somehow don’t exist, and for some reason the movie instead chooses to focus on its cast outrunning the aliens like a standard monster movie.