<u>European Front:</u>
1) US involvement starts with American Public being on the verge of having two sides, as they have a mixed population, and each believes that America should help the other.
2) Roosevelt starts the "Lend - Lease Act", which allows the US to ship supplies and equipment to Britain mainly and other allied countries (Such as USSR).
3) The United States declare war on Germany after Germany, in support of her ally Japan, declared war on the US.
4) The US starts training for their draft. The US builds up all branches of military.
5) The US starts campaign in Africa, & move on to Italy and France.
<u>Pacific Front:</u>
1) The US warns Japan of aggression in China and the Pacific Islands.
2) The US cuts off shipments to Japan, and hold an embargo on Oil
3) The US is warned of impending attacks by Japan, but most are ignored
4) The US's Hawaiian base Pearl Harbor is surprised attack, leading to the loss of much of the US's battle ships
5) The US declares war on Japan, and starts the internment of Japanese-Americans in fear of them being spies & supporters of their home-land
hope this helps