It's an interesting hypothesis. Isolationism was a popular position in America before Pearl Harbor, to the extent that in his 1940 campaign FDR promised he wo

It's an interesting hypothesis. Isolationism was a popular position in America before Pearl Harbor, to the extent that in his 1940 campaign FDR promised he wouldn't enter into a foreign war if he was reelected. And true to his word, after he was reelected America did not declare war on Germany despite many in the press demanding it. Eventually, after Pearl Harbor, it was Germany who declared war on America, not the other way around. After that isolationists in America were quickly silenced. To these isolationists, America declaring war on Germany was one thing but Germany declaring war on America was quite another. Prominent isolationist Charles Lindbergh even sought to sign up for the USAAF in the aftermath of Pearl Harbor. His request was denied by the White House, but he nevertheless helped train American pilots and even flew combat missions as a civilian (which is a bit strange.) It's a very interesting corner of history.