Who was involved and what factors led to war and empire?

describe how the United States and its people went from having no interests in foreign affairs to entering into a war in which America gained an empire. Who was involved and what factors led to war and empire? Finally, in your opinion was America justified in its quest for empire and why and why not?Only use the following link and the uploaded files to write the essay.https://openstax.org/details/us-history