In fairness, the US siding with Germany (or staying neutral) is not as plausible a scenario as people think. Not out of moral principle, of course (save for a few individual actors in the US government) but because Germany and Japan carving out their realms would have been cancerous for the economies of the US and its allies (namely Britain) in the long run, so the Bourgeoisie would never allow it. Especially with Germany outright stating they wanted complete autarky which would have removed America and Britain from those sweet, sweet markets. Of course, the Nazis, having no sense of materialism whatsoever, took this to mean that America, Britain and the USSR were all controlled by the Juice.

Similarly, FDR didn't necessarily want to cultivate ties with the USSR because he liked them. Rather, he considered the British and French Empires to be more immediate threats to :freedom-and-democracy: and, unlike the Soviets who were more conciliatory and reasonable which he mistook for being easy to manipulate, Western Europe would hold on to their colonies to the bitter end (He interestingly had it out for de Gaulle especially). There was actually a lot of tension between the US and the two "Entente" powers even into the Cold War before the latter finally relented, "decolonized" and submitted to American capital. The thing about global capitalism is that there can only really be one "center of world capital", lest the centers come into conflict a la WWI. Bretton-Woods was kind of a foreshadowing for that.

But yeah, world would be a lot better if someone like Henry Wallace took the presidency and continued FDR's plan as opposed to fucking Truman :yes-honey-left: