Who did the U.S. fight against during World War II?

The U.S. fought against Japan, Germany, and Italy during World War II as these nations were part of the Axis powers, which opposed the Allies. Japan was involved in aggressive expansion throughout Asia and the Pacific, initiating conflict with the United States with the attack on Pearl Harbor in 1941. Germany, led by Adolf Hitler, was engaged in extensive military campaigns across Europe and was responsible for the Holocaust and numerous other war crimes. Italy, under Mussolini, was also allied with Germany in its military efforts.

The collaboration between these three nations posed a significant threat to global stability, prompting the U.S. and its allies to mobilize against them. This coalition of nations sought to overthrow the Axis powers, which eventually led to the defeat of these countries by 1945. The other options consist of unrelated countries or conflicts that did not represent direct adversaries during WWII.