<Li> Reported by the joint conference committee on May 16, 1917; agreed to by the House on May 16, 1917 (198--179) and by the Senate on May 17, 1917 (65--8) </Li> <Li> Signed into law by President Woodrow Wilson on May 18, 1917 </Li> <P> The Selective Service Act or Selective Draft Act (Pub. L. 65--12, 40 Stat. 76, enacted May 18, 1917) authorized the United States federal government to raise a national army for service in 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 S. 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 as constitutional by the United States Supreme Court in 1918 . </P> <P> At the time of World War I, the US Army was small compared with the mobilized armies of the European powers . As late as 1914, the Regular Army had under 100,000 men, while the National Guard (the organized militias of the states) numbered around 115,000 . The National Defense Act of 1916 authorized the growth of the Army to 165,000 and the National Guard to 450,000 by 1921, but by 1917 the Army had only expanded to around 121,000, with the National Guard numbering 181,000 . </P>

How did the selective service act prepare the united states for war