Vietnam War: The first draft lottery in the United States is held since World War II.

The United States ran a draft, a system of conscription, during the late 1950s and early 1960s, the peacetime years before the Vietnam War. It was administered by the Selective Service System. In the second half of 1965, with American troops pouring into Vietnam, there was a substantial expansion of the US armed forces, and this required a dramatic increase in the number of men drafted each month.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.