The system by which men aged 18 through 25 register with the U.S. government for military service is called the:

• A. Bill of Rights
• B. Double jeopardy
• C. Equal protection under the law
• D. Selective service

Answer: (D)

The Selective Service System is the government registry that requires men aged 18 through 25 to register for potential military service. This system exists so the government has a pool of eligible individuals ready to be mobilized quickly if Congress and the President decide to implement a draft in an emergency. Even though there is no active draft today, registration remains a legal requirement, and not registering can carry federal penalties. The other options refer to different legal concepts—spelling out fundamental rights, the rule against being tried twice for the same offense, and the idea that laws must treat people equally—but none describe the government registry for military service.