In 1939, World War II had already broken out, and it was a question of whether the United States should participate in it or not. But as the Germans' nature was gradually exposed, and the Barbarossa Plan was launched, the United States could not sit still. Roosevelt immediately contacted Churchill, planning to treat the Soviets as allies and provide them with substantial material assistance.
However, at a critical juncture when the Barbarossa Plan had begun, there was still a different kind of voice in the United States, and that was to sit on the mountain and watch the tiger fight. In particular, Truman, who was a senator at the time and later succeeded Roosevelt as president, put forward a plan to sit on the mountain and watch the tiger fight, and Truman suggested that Roosevelt continue to maintain a neutral position as before, so that both the Soviet union and Germany would lose both sides, and whoever was inferior to the United States would help whom.
This is for the United States to maximize the benefits. However, Roosevelt did not heed these suggestions and firmly sided with the Soviet army. At the beginning of the Barbarossa plan, the Soviet army was completely defeated, and there were people in the United States who feared that the Soviet army would not be able to sustain it. Fortunately, Japan suspended the arrangements for the war against the Soviet Union, otherwise it was really possible for the United States to terminate its assistance to the Soviet Union. Because it is not worth supporting a team that has no hope of victory.
This is the pragmatism that belongs to the United States. In the early days of the Moscow defense, a large amount of aid from the United States continued to reach Murmansk. The Soviets also transferred the garrisons in the Far East back to Moscow to defend the Germans. This laid the foundation for Moscow's victory in defence. What the United States did not expect was that the real target of the Japanese army was Pearl Harbor.
After Christmas 1941, the Japanese attacked Pearl Harbor, inflicting heavy damage on the U.S. Pacific Fleet. At this point, the United States could not think of not going to war. If Roosevelt had heeded Truman's advice, it would have been even more difficult to win the Soviet-German war. What do you think?