Many of the protagonists in Sinclair Lewis' 1920s novels satirized the

While reports of atrocities in concentration camps were significant and troubling, they did not directly prompt the United States to enter the war. Public awareness of these events increased over time but did not catalyze the U.S. military response or official involvement in the conflict.

Germany declared war on the United States on December 11, 1941, three days after the attack on Pearl Harbor. However, the U.S. entry into the war was a response to Japan's actions, making this declaration a consequence rather than the initiating event.

Germany invaded France in May 1940, leading to the swift fall of the French government. While this event was crucial in the early stages of the war, it did not directly lead to the United States joining the fight; U.S. involvement was not prompted until Japan attacked in December 1941.

Japan's invasion of China began in 1937 and was part of a broader military expansion in Asia. The alliance with Germany was also established prior to the U.S. entry into the war, but these actions did not provoke a direct U.S. response until Japan's attack on Pearl Harbor.