According to Pinter's official biographer, Michael Billington, in Harold Pinter, echoing Pinter's own retrospective view of it, The Birthday Party is "a deeply political play about the individual's imperative need for resistance," yet, according to Billington, though he "doubts whether this was conscious on Pinter's part," it is also "a private, obsessive work about time past; about some vanished world, either real or idealised, into which all but one of the characters readily escapes. ... From the very outset, the defining quality of a Pinter play is not so much fear and menace –– though they are undoubtedly present –– as a yearning for some lost Eden as a refuge from the uncertain, miasmic present" (82).
As quoted by Arnold P. Hinchliffe, Polish critic Grzegorz Sinko points out that in The Birthday Party "we see the destruction of the victim from the victim's own point of view:
"One feels like saying that the two executioners, Goldberg and McCann, stand for all the principles of the state and social conformism. Goldberg refers to his 'job' in a typically Kafka-esque official language which deprives the crimes of all sense and reality." ... [Of Stanley's removal, Sinko adds:] "Maybe Stanley will meet his death there or maybe he will only receive a conformist brainwashing after which he is promised ... many other gifts of civilization...."
In an interview with Mel Gussow, which is about the 1988 Classic Stage Company production of The Birthday Party, later paired with Mountain Language in a 1989 CSC production, in both of which David Strathairn played Stanley, Gussow asked Pinter: "The Birthday Party has the same story as One for the Road?"
In the original interview first published in The New York Times, on 30 December 1988, Gussow quotes Pinter as stating: "The character of the old man, Petey, says one of the most important lines I've ever written. As Stanley is taken away, Petey says, 'Stan, don't let them tell you what to do.' I've lived that line all my damn life. Never more than now."
In responding to Gussow's question, Pinter refers to all three plays when he replies: "It's the destruction of an individual, the independent voice of an individual. I believe that is precisely what the United States is doing to Nicaragua. It's a horrifying act. If you see child abuse, you recognize it and you're horrified. If you do it yourself, you apparently don't know what you're doing."
As Bob Bows observes in his review of the 2008 Germinal Stage Denver production, whereas at first " 'The Birthday Party' appears to be a straightforward story of a former working pianist now holed up in a decrepit boarding house," in this play as in his other plays, "behind the surface symbolism ... in the silence between the characters and their words, Pinter opens the door to another world, cogent and familiar: the part we hide from ourselves"; ultimately, "Whether we take Goldberg and McCann to be the devil and his agent or simply their earthly emissaries, the puppeteers of the church-state apparatus, or some variation thereof, Pinter's metaphor of a bizarre party bookended by birth and death is a compelling take on this blink-of-an-eye we call life."