1920s: Calvin Coolidge is elected President of the United States. After Woodrow Wilson—an intellectual who tried to persuade the reluctant, isolationist United States to join the League of Nations—Coolidge is a drastic change. While Wilson was cerebral and visionary, Coolidge is practical and bourgeois. Advancing U.S. business interests is his primary concern.

Today: In the election to succeed, U.S. President Bill Clinton, Vice President Al Gore, and Texas Governor George W. Bush face-off. After the closest election in American history, the Supreme Court declares Bush the winner.

1920s: The aftereffects of World War I continue to resonate in defeated Germany. Because of its need to pay off massive war reparations, the German government simply prints more money. The effect is massive inflation, so much so that in the 1920s German shoppers must bring wheelbarrows full of cash in order to...