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.

The United States at War Series is a collection of presentations that review the political, economic, and social forces that have erupted in military conflict. They describe the historical context for each of the nine major U.S. wars and examine how a military conflict resolved, or failed to resolve, the forces that caused the war.