Origins

• Although it is not explicitly expressed in the US Constitution, the ability to issue a war draft comes from the implicit meaning of Congress' abilities to "raise and support Armies" in times of war. If invoked, the draft is controlled by the Selective Service System (SSS), who is in charge of determining who will be entered into the draft lottery.
  
  

Wars

• The draft has only been enacted five times in American history: the Civil War, World War I and II, the Korean War and the Vietnam War. Each incidence required the government to officially declare war on another entity to enact the draft.
  
  

Registration

• The Selective Service System (SSS) was established as the operating body of the draft in 1917 for World War I and continues to be the primary body through which men must register after the age of 18. This was preceded by the National Conscription Act of 1863 that created a lottery system where men could have been drafted for the Civil War.
  
  

Induction Centers

• Once a man's number has been called up to draft, he must report to the induction center closest to his home within an allotted period. He'll train to enter combat there or be sent to another center or military installation to learn the necessary skills. Failure to report could result in legal action; many men chose to flee the country during times of draft rather than report for duty.
  
  

Resentment

• Although there was no time that the population was completely pleased about the draft, tensions rose to an all-time high during the Vietnam War, the last draft in American history. Protesters lined the streets of Washington, D.C. and other metropolitan areas for demonstrations to show their displeasure.