The important outcome is, after Japan bombed Pearl Harbor. The United States switched from supplying supplies to allies, to gathering up men and fighting. They were two theaters, or fronts where the men fought. The Pacific Theater and the European Theater. Mostly United States Marines were brought in for the Pacific, and Army did Europe. Plus Navy aiding Marines due to Navy having semi control over the Marines due to them being under the Department of the Navy. And obviously years of fighting paid off, due to us pushing them into their own land of Japan. And sending two atomic bombs to seal the deal, which actually could have been three. Due to them having a third one, just never used it. However we blocked a major invasion which could have lead to an easier way of invasion due to all of those lands being near California. As well Japan had plans to go into Australia, however Germany and USA was fighting in that front as well. But we'll save that for another time. Hope this helps, have a nice day!