The film has been read as both an allegory for the perceived loss of personal autonomy in the Soviet Union and as an indictment of McCarthyist paranoia about Communism during the early stages of the Cold War.
As Adam Roberts wrote in Science Fiction; The New Critical Idiom:
Indeed [the film] can be read both as right-wing McCarthyite scaremongering—Communists from an Alien place are infiltrating our American towns and wiping out their American values, and the worst of it is they look exactly like Americans—and as left-wing liberal satire on the ideological climate of conformism that McCarthyism produced, where the lack of emotion of the podpeople corresponds to the ethical blind eyes turned by Americans to the persecutions of their fellows by over-zealous McCarthyites.
Despite the general agreement among film critics regarding these political connotations of the film, lead actor Kevin McCarthy said in an interview included on the 1998 DVD release that he felt no political allegory was intended. The interviewer stated that he had spoken with the author of the original novel, Jack Finney, who also professed to have intended no specific political allegory in the work.
In his autobiography, "I Thought We Were Making Movies, Not History", Walter Mirisch writes: "People began to read meanings into pictures that were never intended. The Invasion of the Body Snatchers is an example of that. I remember reading a magazine article arguing that the picture was intended as an allegory about the communist infiltration of America. From personal knowledge, neither Walter Wanger nor Don Siegel, who directed it, nor Dan Mainwaring, who wrote the script nor the original author Jack Finney, nor myself saw it as anything other than a thriller, pure and simple".