Selective Service is the way the U.S. Government prepares for a military crisis. A person is not inducted into the military by registering, but may be drafted in a military crisis. www.sss.gov

Illegal aliens living in the USA must register and do not require a social security number to do so.

Tourists, students and members of a diplomatic corp or trade mission and their families need not register.

If you fail to register when you were required to do so, you may find yourself being denied naturalization. It is possible to apply for Naturalization after you turn 32, if you failed to do so. However, you must provide good reasons why you did not register, when you should have done so.