With a POD in the 1930s, make a scenario where the US and the USSR engage in a major, conventional war against each other, either in China, Europe, or elsewhere. My personal scenario is (although largely impossible) Einstein remaining in Germany, and the Manhattan Project never occurring due to both Germany and Japan losing quicker than OTL - and then a superiority in conventional arms leading Stalin to launch an all-out war against the United States in Europe and in other regions around the world.