By the turn of the twentieth century, the United States had evolved from a colony into an international power. As a result of the Spanish-American War, America acquired colonies in both the Atlantic and Pacific Oceans. She also acquired a taste for international politics.

Then the First World War erupted. As it dragged on, Americans fiercely debated U.S. involvement; the nation had a deep tradition of avoiding foreign wars. But the Spanish-American War had challenged this tradition, and the First World War would shatter it.