Why We Fight: Prelude to War | When the World Goes to War, Part 1

Why We Fight — Part 1: Prelude to War Before the battles. Before the invasion of Poland. Before Europe was engulfed in the Second World War, a series of political, economic, and military events were setting the stage for a conflict that would reshape the world. Prelude to War is the first film in the historic Why We Fight series, originally produced during World War II to explain the forces and events leading to America's involvement in the conflict.