I think a few here is fond of the old Franklin Delano Roosevelt, but looking into the actions that he did during the years into the prelude of World War 2 was really interesting. At his behest, he supplied Joseph Stalin and the whole Soviet Union of military equipment and intelligence to prepare for the Nazis. I really don't think that Americans during at the time was on board with supplying another enemy, the communists, with their own handmade products just to hold off the Reich.
Let's not get started with the internment camps he did against Americans of Japanese lineage after the Pearl Harbor attacks, how the Democrats were tight-lipped about it to this day, and the communist project that the former First Lady, Eleanor Roosevelt did in Arthurdale, Virginia, that was still left untold on how many people died due to starvation on that god forsaken experiment of hers.
So we have OP claiming that FDR's great crime was that he helped the USSR beat off the Germans, and here we have a claim that FDR did not care at all about defeating Germany. Which is it? Also, have you heard of something called 'constraints'? A president is not a dictator, and it has often been remarked that Germany did FDR a favor by declaring war, because that would have been quite difficult.