All men ages 18-25 must register for the Selective Service, even if there is no active draft, as a part of their civic duty. It is required by law and necessary to prepare the country for national emergencies. This system makes the draft fair if it becomes needed – young men are selected by lottery based on age and random numbers.
Section "Learn and Explore" uses official instructions and media files of US Citizenship and Immigration Services, US National Museum of American History, The Smithsonian Institution and other governmental and public organization.