Due to a controversial comment about the Polish-German post-war border, favoring Germany, the speech improved German-American relations while simultaneously worsening Polish-American ones.
In his speech, he left the final extent of the area east of the Oder Neisse that would become permanently Polish to be decided in the future: "The Soviets and the Poles suffered greatly at the hands of Hitler's invading armies.
The purpose of the speech and associated US diplomatic activities was as propaganda aimed at Germany by the Western Powers, which could then blame the Polish-German border and the German expulsions on Moscow alone.
[2][9]Olszewski[clarification needed] asked the US ambassador to Poland for an explanation and claimed that the speech would have a negative impact on the Poles from beyond Curzon Line that were moving into western territories.
[8] Ambassador Arthur Bliss Lane tried to reassure Poles that Byrnes's speech should not be interpreted as Americans' desire to avoid their obligations made at Potsdam.
Eventually, he learned, after discussing the issue with members of Department of State, that the speech was intended to "smoke out Molotov's attitude on the eve of elections in Germany".
[3][5] With backing from the UK and from France, he also advocated the establishment of a four-power commission that would be given the task of deciding the extent of the new border revisions in favor of Germany.