Men were required to register for military service was a result of the Selective Service Act
Explanation:
During the Civil War of America, compulsory enlistment or ‘conscription’ was started wherein all able bodied men were compulsorily required enlisting in the army and fighting in the civil war.
It was however, common practice for wealthy men to pay for substitutes in their place to fulfil their service obligations. Woodrow Wilson, in turn introduced in 1917, the selective service act which 2.8 million men were inducted within the Army during the course of 2 years and thereby abolishing the bounty system.