The surveillance employed by the State is intrusive and assertive; it holds power over the citizens, making the state authoritarian, which Auden would certainly be opposed to given that he was quite anti-Authority.
Through constant oscillation between the imagined and the tangible, Auden presents the problem of love; even when the “you” only exists in the imagined past, the speaker cannot help but try, through language, to bring them into the tangible present.