The purpose of the Selective Service Act was to allow the U.S. government to draft soldiers after the United States entered World War I. At the time of the Selective Service Act, the Western Front was in dire need of troops.
The Selective Service Act was passed by the U.S. Congress on May 18, 1917, about six weeks after the United States entered into World War I. The act required that men between the ages of 21 and 30 register to be drafted into military service. The age range was later expanded to men aged 18 to 45. In April of 1917, only about 100,000 men had volunteered for military service. Within several months of passing the act, that number increased to over 10 million. The act bolstered the number of Allied men fighting on the western European battlefields.
The first draft that occurred in peacetime was instituted by President Franklin Roosevelt in 1940 as the Selective Training and Service Act. It expired in 1947. This act was resuscitated in 1948 and continued through the Vietnam War. The Selective Service acts were considered the most fair and democratic way to ensure the United States had enough troops in active service.