1. It should be noted that the leaders of American Jews (such as Stephen Wise) objected strongly to any special efforts to save European Jews. Just as the British feared the Jewish survivors would destabilize their Empire by moving to Palestine, American Jews feared that most East European Jews were either Orthodox or Socialist, and would undermine the pro-assimilation policies they were favoring. Note that whereas 50 years ago it was argued that the main evidence for American knowledge of the holocaust was that the tiny frum minority was asking for the US and UK to help European Jews, we now now that the allies broke the German codes early in the war, and that Allied leaders were fully informed of the holocaust throughout the wall.
2. Roosevelt appointed Jews to higher positions than any previous president, and took a strong stand against discrimination. It can also be argued that his support of going to war against Germany was a politically courageous decision that saved the lives of the many European Jews who did survive (public opinion in the USA preferred concentrating on Japan and trying to avoid war with Germany, in part reflecting the unpopularity of both the Soviet Union and the British Empire in America).