The Selective Service Act or Selective Draft Act () authorized the federal government to raise a national army for the American entry into World War I through conscription. It was envisioned in December 1916 and brought to President Woodrow Wilson's attention shortly after the break in relations with Germany in February 1917. The Act itself was drafted by then-Captain (later Brigadier General) Hugh Johnson after the United States entered World War I by declaring war on Germany. The Act was canceled with the end of the war on November, 1918. The Act was upheld by the United States Supreme Court in the Selective Draft Law Cases in 1918, a decision based partially on Vattel's The Law of Nations of 1758.