May 18 (UPI) -- In May 1914, just six weeks after the United States' entry into World War I, the country faced a monumental crisis.
Military planners estimated that the U.S. needed to field a 1 million-man Army in Europe, but just 73,000 men had stepped forward to enlist.
This lack of volunteerism left the United States in a precarious and dangerous position.
To fill the void, on May 18, 1917, President Woodrow Wilson signed the Selective Service Act, the nation's first conscription law since the Civil War, requiring all men between the ages of 21 to 30 to enlist in the armed forces.
Over the course of its 240-year history, the United States has instituted a military draft in five conflicts: the Civil War, World War I, World War II, as well as the Korean and Vietnam Wars.
During the Civil War, the governments of both the Confederacy and the Union passed conscription laws to bolster their ranks, though each side also allowed for the unpopular "substitutes" provision which permitted the wealthy to "buy" their way out of service.
When drafting the Selective Service Act, members of the 65th Congress looked to history to correct previous wrongs, writing into law, that "no person liable to military service shall hereafter be permitted or allowed to furnish a substitute for such service."
By the end of the first World War, and the sunsetting of the legislation, draftees accounted for more than half of the 4.8 million Americans who served in the armed forces.
It would be 20 years before conscription would return to the forefront of U.S. politics. When it did, it would usher in the first peace-time draft in U.S. history.
The Selective Training and Service Act of 1940 initially required that all men between the ages of 21 to 35 register for the draft, with those called up serving for 12 months. This was later revised to 18 months of mandatory service.
Shortly after the Japanese attack on Pearl Harbor, Congress amended the law and mandated that all men between the ages of 20 to 44 were eligible for military service while requiring all men between the ages of 18 and 64 to register. Additionally, the service period was extended to last the duration of the war.
All told, wartime draftees numbered more than 10 million men, and the 1940 Act remained in effect until 1947.
The draft was brought back during the Korean War, and while the number of exemptions and draft evasion cases increased during this time, it would be its use during the United States' involvement in the Vietnam War that would bring about massive social upheaval.
In a decision that would have far-reaching consequences, not just for the Army, but for the nation as a whole, President Lyndon Johnson resisted the idea of mobilizing Reserve units, instead relying on larger draft calls and voluntary enlistments.
As the conflict in Southeast Asia escalated, many took to burning their draft cards to protest the war. Anti-war demonstrations spread across the country with hundreds of thousands marching in Washington and across the United States.
Civil rights activist Stokely Carmichael said during a protest in New York City on April 15, 1967, "The draft exemplifies as much as racism the totalitarianism which prevails in this nation in the disguise of consensus democracy."
One of the defining events of the era were the May 4, 1970, shootings at Kent State University where four students died after members of the Ohio National Guard opened fire during anti-war protests on the campus.
As the war in Vietnam dragged on, support for both it, and for the draft, declined. It was during the 1968 presidential election that Richard Nixon campaigned on the promise of ending the draft and transitioning to an all-volunteer Army.
Following the signing of the Paris Peace Agreement on January 27, 1973, Defense Secretary Melvin R. Laird announced, "I wish to inform you that the Armed Forces henceforth will depend exclusively on volunteer soldiers, sailors, airmen and Marines. Use of the draft has ended."
While this was not the "official" end of the draft, the Selective Service System remained intact and still required all men, starting at 18 years of age, to register.
It's been more than 40 years since the last draft ended, and though in 1980 President Jimmy Carter reinstated the requirement for young men to register with the Selective Service System, the conscription of males into military service has never been more than a faint whisper.
Rep. Charles Rangel, D-N.Y., a Korean War veteran and vocal critic of the Iraq War, sought to reintroduce the draft as a means of sharing the sacrifice. Rangel and others on the left believed that if Americans are once again vulnerable to being drafted, the choice to go to war will not be an inevitable outcome.
Secretary of Defense James Mattis offered the following during his Senate confirmation hearings, "Our military is the envy of the world, representing America's awesome determination to defend herself," he said. "Working with you, I will endeavor to keep our unique all-volunteer force second to none."