The Twenty-sixth Amendment (Amendment XXVI) to the United States Constitution establishes a nationally standardized highest permissible minimum age of 18 for participation in state and federal elections. It was proposed by Congress on March 23, 1971, and three-fourths of the states ratified it by July 1, 1971.
Various public officials had supported lowering the voting age during the mid-20th century, but were unable to gain the legislative momentum necessary for passing a constitutional amendment.
The drive to lower the voting age from 21 to 18 grew across the country during the 1960s and was driven in part by the military draft held during the Vietnam War. The draft conscripted young men between the ages of 18 and 21 into the United States Armed Forces, primarily the U.S. Army, to serve in or support military combat operations in Vietnam. This means young men could be required to fight and possibly die for their nation in wartime at 18. However, these same citizens could not have a legal say in the government's decision to wage that war until the age of 21. A youth rights movement emerged in response, calling for a similarly reduced voting age. A common slogan of proponents of lowering the voting age stated "Old enough to fight, old enough to vote".
Determined to get around inaction on the issue, congressional allies included a provision for the 18-year-old vote in a 1970 bill that extended the Voting Rights Act. The Supreme Court subsequently held in the case of Oregon v. Mitchell that Congress could not lower the voting age for state and local elections. Recognizing the confusion and costs that would be involved in maintaining separate voting rolls and elections for federal and state contests, Congress quickly proposed and the states ratified the Twenty-sixth Amendment.
The framers of the U.S. Constitution did not establish specific criteria for national citizenship or voting qualifications in state or federal elections. Before the Twenty-sixth Amendment, states had the authority to set their own minimum voting ages, which was typically 21 as the national standard.
An effort to reduce the age limit to 18 nationally began to gain serious traction during World War II. This came about after 18 & 19 year old men started being drafted and some of the public showed concern about this possibility and not being able to vote. The age limit was not reduced nationally during the war due to a variety of factors including a perceived lack of maturity, President Franklin D. Roosevelt not regarding youth suffrage as an important issue, and most members of Congress believed it would interfere in the rights of states with regards to setting their own rules about voting. Senator Harley Kilgore began advocating for a lowered voting age in 1941 in the 77th Congress. On October 17, 1942 the first attempt to lower the voting age nationally occurred when Representative Victor Wickersham of Oklahoma proposed an amendment to do so which applied to just the federal level. A few days later Senator Arthur Vandenberg of Michigan initiated a separate one which was a resolution and went further applying to the federal and state level. Vandenberg had a track record of showing interest in young people with Wickersham having a close relationship with young people in his constituency and in general while Vandenberg had previously introduced constitutional amendments banning child labor for those under 16 years old. Neither proposals from Wickersham or Vandenberg passed through Congress.
Despite the support of fellow senators, representatives, and First Lady Eleanor Roosevelt, Congress failed to pass any national change. However, public interest in lowering the voting age became a topic of interest at the local level. In 1943 and 1955 respectively, the Georgia and Kentucky legislatures approved measures to lower the voting age to 18 and several other localities lowered the voting age in the 1950s including the Hawaii and Alaska Territories along with Guam. President Harry S. Truman did not publicly indicate whether he supported lowering the voting age to 18 years old.
President Dwight D. Eisenhower, in his 1954 State of the Union address, became the first president to publicly support prohibiting age-based denials of suffrage for those 18 and older. During the 1960s, both Congress and the state legislatures came under increasing pressure to lower the minimum voting age from 21 to 18. This was in large part due to the Vietnam War, in which many young men who were ineligible to vote were conscripted to fight in the war, thus lacking any means to influence the people sending them off to risk their lives. "Old enough to fight, old enough to vote" was a common slogan used by proponents of lowering the voting age. The slogan traced its roots to World War II, when President Roosevelt lowered the military draft age to 18.
In 1963, the President's Commission on Registration and Voting Participation, in its report to President Lyndon B. Johnson, encouraged lowering the voting age. Johnson proposed an immediate national grant of the right to vote to 18-year-olds on May 29, 1968. Historian Thomas H. Neale argues that the move to lower the voting age followed a historical pattern similar to other extensions of the franchise; with the escalation of the war in Vietnam, constituents were mobilized and eventually a constitutional amendment passed.
Those advocating for a lower voting age drew on a range of arguments to promote their cause, and scholarship increasingly links the rise of support for a lower voting age to young people's role in the civil rights movement and other movements for social and political change of the 1950s and 1960s. Increasing high-school graduation rates and young people's access to political information through new technologies also influenced more positive views of their preparation for the most important right of citizenship.
Between 1942, when public debates about a lower voting age began in earnest, and the early 1970s, ideas about youth agency increasingly challenged the caretaking model that had previously dominated the nation's approaches to young people's rights. Characteristics traditionally associated with youth—idealism, lack of "vested interests", and openness to new ideas—came to be seen as positive qualities for a political system that seemed to be in crisis.
In 1970, Senator Ted Kennedy proposed amending the Voting Rights Act of 1965 to lower the voting age nationally. On June 22, 1970, President Richard Nixon signed an extension of the Voting Rights Act that required the voting age to be 18 in all federal, state, and local elections. In his statement on signing the extension, Nixon said:
Despite my misgivings about the constitutionality of this one provision, I have signed the bill. I have directed the Attorney General to cooperate fully in expediting a swift court test of the constitutionality of the 18-year-old provision.
Subsequently, Oregon and Texas challenged the law in court, and the case came before the Supreme Court in 1970 as Oregon v. Mitchell. By this time, four states had a minimum voting age below 21: Georgia, Kentucky, Alaska, and Hawaii.
During debate of the 1970 extension of the Voting Rights Act, Senator Ted Kennedy argued that the Equal Protection Clause of the Fourteenth Amendment allowed Congress to pass national legislation lowering the voting age. In Katzenbach v. Morgan (1966), the Supreme Court had ruled that if Congress acted to enforce the 14th Amendment by passing a law declaring that a type of state law discriminates against a certain class of persons, the Supreme Court would let the law stand if the justices could "perceive a basis" for Congress's actions.
President Nixon disagreed with Kennedy in a letter to the Speaker of the House and the House minority and majority leaders, asserting that the issue was not whether the voting age should be lowered, but how. In his own interpretation of Katzenbach, Nixon argued that to include age as a possible parameter of discrimination would overstretch the concept, and voiced concerns that the damage of a Supreme Court decision to overturn the Voting Rights Act could be disastrous.