While I agree with you that Wendell Willkie was an interventionalist (remember that interventionalists wanted to help as much as possible WITHOUT going to war), it certainly does not make Roosevelt an isolationist. There are a ton of things that I can critisize FDR on but how he handled our eventual entry into the war is not one of them. At least not from a major standpoint.
He had to contend with the isolationist crowd that were adamant even after Germany went to war with Britain and France not to allow the United States to go to war. You'll notice that his speech after Pearl Harbor doesn't even mention Germany. One reason for this was that even after that attack FDR knew that he could not request a general war with Japan and Germany. The isolationists still would not have had it. Hitler had to do us that favor by declaring war on the U.S. on the 11th. This was despite the fact that Lend Lease had us trading arms as fast as we could ship them and his giving authority to Atlantic naval units to attack German submarines on sight (already an act of war). There were some logistical and preparedness issues that I think fall at FDR's feet and not just some of the people who fell on the sword upon our entry into the war, but I think he did just about as well as a politician can under the circumstances.
“There are a ton of things that I can critisize FDR on but how he handled our eventual entry into the war is not one of them. At least not from a major standpoint.”
You are basically repeating all of the liberal historian’s talking points. FDR moved quickly only after the Soviet Union was attacked by the Nazis. FDR was behind the public opinion on helping England . . don’t let the liberal apologists and myth makers deceive you.