Mandatory national service (also called compulsory service) is a requirement, generally issued by the federal government, that people serve in the military or perform some other type of national service. In the United States, the Selective Service System is responsible for maintaining information on those potentially subject to military conscription. The Military Selective Service Act requires essentially all males between the ages of 18 and 26 to register with the Selective Service System, regardless of whether there is an active draft.
For 39 years, it's been a rite of passage for American men. Within 30 days of his 18th birthday, every male citizen and legal resident is required to register for the draft. Failure to do so can result in serious consequences, such as being ineligible for federal student financial aid, job training programs, and even federal employment. In the past, registering for FAFSA meant that you must also sign up for the draft. Submitting the FAFSA no longer requires registration for the Selective Service, but it is still a mandatory requirement for all males.
In 1917, the Selective Service Act created a system that authorized a draft and required men to register with the government in case of a national emergency. The requirement that only men — but not women — register for the draft is one of the last examples of overt sex discrimination written into federal law. However, the country remains divided on whether women should be eligible for the draft if it is ever reinstated.