The speech was a kind of response (albeit delayed 22 months from its start) to the building of the Berlin wall. The Berlin wall symbolized a barrier between East and West, and its construction meant the ideological differences between the two were so significant that the free movement of people between the sides needed a physical barrier. The city which before the wall was beginning to regain some of its former standing was fractured by a war, and with its concrete "reparation" it was split, doomed to endure its memories as a pseudo-city divided by its invaders. Kennedy tried to highlight its spirit as a "whole," and as a symbol to the indomitable spirit of democracy and capitalism in the face of totalitarianism - despite the obvious wall there splitting it apart. I think he'd wanted to make the city less about the Wall and more about standing firm in the face of what the wall did - which was to separate conquered peoples and divide spoils.

It was pretty clever, considering the whole soviet propaganda/philosophy aimed at statements like "workers of the world unite!" And their posters endlessly derided the united States for its aggression while trumpeting the soviet aim for peace. He made a soundbyte out of the idea that Berlin was a city of its people and not a city of current or former barbarians, regardless the physical and political realities.