During which conflict did the U.S. first employ the draft in the 20th century?

The United States first employed the draft in the 20th century during World War I. The Selective Service Act was enacted in 1917, which allowed for the conscription of men into military service as the country entered the conflict. This marked a significant development in U.S. military policy, transitioning from a volunteer army to one that could be supplemented by conscripted soldiers during major conflicts. The draft played a crucial role in mobilizing millions of American troops to support the Allied forces in the war. While subsequent conflicts, such as World War II, the Korean War, and the Vietnam War, also utilized the draft, it was World War I that marked its initial implementation in this century.