They didn’t share a border until the Soviets and NAZIs jointly invaded their neighbor Poland.

Exactly, the country that shared a massive land border with the NAZIs and was a direct target of their aggression suffered many more casualties than the ones what didn’t, who’da thunk it? Without the combined efforts of essentially the entire rest of the world, the USSR would have been toast.

And the Ukrainians, and the Poles, and the French resistance, and the British, and the Americans, and the Canadians, and…