And outside of Europe, a huge number of capitalist democracies didn't join in or pick a side until late 1941 (6 months after the invasion of the USSR), at the same(ish) time as the US joined.

Just i know there were preferred trading partners and aide packages from countries to one side or the other, but if Perl Harbor hadn't happened, it was by no means certain the US and many other countries would have entered the war and instead just let it settle itself.

Of course Europe was involved in the European war. Turns out Europe is only a small part of the world tho.