The drafting ages refer to the age range within which men are required to register for the Selective Service System, also known as the military draft or conscription. The Selective Service System requires almost all male U.S. citizens and immigrants, ages 18 through 25, to register with the government. The age limit was later raised in August 1918 to a maximum age of 45, but the military draft was discontinued in 1920. The Selective Training and Service Act of 1940 required all men between the ages of 21 and 45 to register for the draft, and this was the first peacetime draft in United States history. Currently, if a draft were held today, those who are 20 years old -- or turning 20 during the year in which the numbers are drawn -- would be the first to go. Beginning Jan. 1 of the year an eligible male turns 21, he would drop into the second priority category, and men born the following year would move into the priority group one. Here is a summary of the drafting ages:

• Men aged 18 through 25 are required to register with the government.
• The age limit was raised to a maximum age of 45 in August 1918, but the military draft was discontinued in 1920.
• The Selective Training and Service Act of 1940 required all men between the ages of 21 and 45 to register for the draft.
• If a draft were held today, those who are 20 years old -- or turning 20 during the year in which the numbers are drawn -- would be the first to go.