1950s America may be characterizied by a rising fear amoung the population that communists were slowly infiltrating every corner of society. Politicians, celebrities, your friendly neighbours across the road might be accused, without proper evidence, of being commi spies, such was the level of fear generated by politicians looking for votes. Put enough fear in a person and they'll do anything you ask; give you their lunch money; vote for you; go to war for you. Reason starts to fail and their minds become malleable. Films released at this time exploited this real fear. Monster mutation movies examined, comically, the possible effects of a nuclear fallout, horror movies like "Invasion of the Body Snatchers" directed by Don Siegel in 1956 may, arguably, have used its story, of an Alien life form secretly inhabiting the body of your average American, as an allegory of the communist threat at the time.
In small town America, a doctor discovers that some of his patients have become suspicious of their loved ones, that theyre not quite themselves. Though sceptical at first, this is proved to be true in the most horrifying way. His close freind finds a clone of himself growing in his house. These clones are somehow coming alive, assuming the personalities of the original, then offing the original. Slowly, one by one, this life form is colonising America.
Some films tend to get a bit preachy about hot topics. A film about hostile invaders taking over America would resonate with alot of concerned citizens who might look for some sort of catharsis from thier fears. But theres more to this film than just cashing in on a "hot" idea. What this film does so well is pure and basic, it entertains. And the references to politics may only be in hindsight. With the directors ability to creates suspenseful, edge of your seat scenes with a genuinly engaging dialogue, its hard to believe that Don seigel would rely on such dirty tricks alone.