Answer:
The United States practiced a strict policy of isolation. This means that it would not join alliances or wars on other continents and will only look into its own needs as a nation. The best they could do was to embargo Japan. Besides this, the people in the United States did not want war. Most people that wanted war wanted to support Britain but against Germany and not Japan. So to go to war with Japan they needed a good cause. After the bombing of Hawaii, the public was outraged and the nation had a good reason to enter the war.
