Wars are expensive, and nations at war need to raise a great deal of money. Higher taxes raise some money, but usually not enough. The solution in the United States during the twentieth century has been war bonds.

An American propaganda poster, circa 1917, designed to entice citizens into buying war bonds to support U.S. efforts during World War I. Courtesy of Hoover Institution Archives.

In buying a war bond, a citizen is loaning money to the government, at a given rate of interest, to be repaid years later, when the war is over. In World War I (1914–18), these notes were called Liberty Bonds. They were touted at bond rallies, endorsed by movie stars, and the subject of speeches by civilian volunteers called the Four Minute Men. Similar strategies were used during World War II (1939–45) to sell bonds. Some of the most successful bond rallies, attended...