Nazi Germany declared war on the USA. It was only logical to ally with Stalin, under the "'enemy of my enemy" rule (see how well it works?).

Remember: the USA does not have permanent allies, it only has permanent interests. And in WWII, America's interests were to help Britain (and capitalist liberalism) survive in Europe, and defeat imperial Japan in the Pacific.

FDR actually started the lend-lease program to Russia ILLEGALLY in 1940 without the approval of Congress, in order to put pressure on Hitler and stave off a German invasion of "that sceptred isle".

As far as those dark histories of Eastern Europe and the Baltics is concerned, I do not feel it is up to me to address them at this time. IF, however, we get another situation like Ukraine, i.e., where a bunch of unreconstructed Nazi Russophobes want to start WWIII, I will do my best to alert my countrymen that we really should not be funding and supporting Nazis - despite the cynical predilections of our leaders.

Now, that day may, unfortunately, come sooner than we think. There is no shortage of hatred for the Russians among the Baltic peoples. They, like Ukraine, also had their own Waffen SS Divisions that fought at Stalingrad. That was surely a factor in how they were treated by the occupying Russians post-war. No love lost, there. I get it. But they are all part of NATO now, and so they seem in many ways to be even more provocative, because they think they can do whatever they want, and Article 5 will protect them. They are WRONG. See my comment about US allies above. NATO's Article 5 does not mean the US will "automatically" come to the aid of a member country that is attacked. And it certainly does not obligate anyone to help out a member that attacks another State. Right now, the Baltics are acting like a tough little guy who has a big bully standing behind him. They may find that if things get hot, they will turn to find that big protector is nowhere to be seen.

Just ask Georgia's Mikheil Saakashvili. That's what happened to him in 2008.