In 1941, the Lend Lease Act enabled all U.S. military to support allied countries with weapons and other suppllies.
Japanese interned to keep them out of military zones and to make the Military feel safe to know that there aren't any saboteurs s or eespionage.
In 1941, President Roosevelt met with the prime minister of Great Britain to work out a plan to defeat the Axis powers. Roosevelt wanted to put Europe first in it plans to defeat the Axis.
Ever since December 7, 1941, The U.S. started facing the Japanese. They started Island hopping which is when you took the most strategically important islands instead of the Japanese held ones.
The Pacific Allied war planners thought about invading Japan. However, there would be more than 1 million Allied casualties. They came up with another idea. The scientists started the Manhattan]en project in 1942. This is where they fist started atomic bomb testing which eventually led to the bombings of Nagasaki and Hiroshima in 1945.
The cold war started between the U.S. and USSR because of different political beliefs.