"During the Civil War, the U.S. Congress passes a conscription act that produces the first wartime draft of U.S. citizens in American history. The act called for registration of all males between the ages of 20 and 45, including aliens with the intention of becoming citizens, by April 1. Exemptions from the draft could be bought for $300 or by finding a substitute draftee. This clause led to bloody draft riots in New York City, where protesters were outraged that exemptions were effectively granted only to the wealthiest U.S. citizens." - History.com