Final answer:
After the U.S. entered wars, draft legislation was adapted to meet military needs, leading to extensive conscription in both World Wars and the eventual abolishment of the draft post-Vietnam War, alongside the enactment of the War Powers Act.
Step-by-step explanation:
Changes to US Draft Legislation After Declaring War
After the United States declared war, there were significant changes to draft legislation and U.S. policy. Initially, there was hope to maintain an all-volunteer army, but due to the size of the enlisted army and the National Guard being insufficient, the draft was deemed necessary.
Following later conflicts, the draft was eventually abolished, and the War Powers Act of 1973 was passed to limit the president's power to commit U.S. forces to combat without a declaration of war by Congress.
In World War I, there were concerns about volunteer enlistment being haphazard and not sufficiently increasing army size. This necessitated the implementation of the draft, resulting in roughly 60 percent of nearly 4 million soldiers being draftees by the end of the war.
Conversely, during World War II, a peacetime draft had already been established in September 1940, but further expansion was required, leading to approximately fifty million men registering for the draft, with ten million inducted into service.
Government control over the economy and production also expanded significantly during the wars, with precedents often being set by the British model.
Changes in society followed, as wars required the mobilization of entire societies, leading to rationing, price controls, and altered workforce demographics with increased opportunities for women and minorities.