Aha! Touched a nerve, innit?
I like Churchill, overall - even if he was a raging racist imperialist, he did give a some good speeches against Hitler and was the moral force against the Axis, and later, against the Soviets. Some of the best quotes in history summing up the hopes and the ironies of democracy as a system of government.
But let's not kid ourselves. In terms of hard power, in this grouping of 3, he was the junior partner. And Churchill knew it.
Why do you think Churchill spent every other day on the phone with FDR begging him to get involved in Europe? In response, FDR pioneered Lend-Lease, but the U.S. was very much short of entering WWII on Britain's behalf, until the Japanese resolved that question with Pearl Harbor.
So, be lucky:
--That America was led by a liberal internationalist like FDR, who understood the stakes in Europe, rather than a conservative isolationist anti-Semite like, say, Charles Lindbergh.
--That Hitler foolishly declared war on the U.S. after Pearl Harbor, honoring his alliance with Japan, but also putting Nazi Germany on the map for the U.S.
Had Hitler not declared war on the U.S., it's conceivable the U.S. would have only fought in the Pacific Theater, lending only token support to Britain. The European Theater of WWII would have looked a lot different. Britain and the USSR (without America) vs. Nazi Germany may have resolved as a stalemate.