President Wilson's hopes of world peace through collective security clash at Versailles with European politicians who want to punish Germany, sowing the seeds of World War II.

The U.S. Senate wins a battle with the president for control of foreign policy; President Wilson suffers a stroke while traveling by train to promote the League of Nations.

In 1921, the post-wars arm race is limited by the world's first major disarmament conference; U.S. Gen. Billy Mitchell demonstrates air power's potential by bombing obsolete battleships in the Chesapeake Bay.

Disillusioned by the horrors of World War I, the U.S. tries to isolate itself from the rest of the world, imposes strict immigration quotas and ushers in racism and ethnic discrimination.

The traumatic Great Depression shatters U.S. self-confidence and paralyzes foreign policy, leading to further isolationism while dictators rise to power abroad.

Contrasting the styles of FDR and Hilter to show how individual charisma and technological changes can change history.