Barry Morris Goldwater (January 2, 1909 – May 29, 1998) was a five-term United States Senator from Arizona (1953–1965, 1969–87) and the Republican Party's nominee for President in the 1964 election. He was a Major General in the U.S. Air Force Reserves. He was also referred to as "Mr. Conservative".

Goldwater is the politician most often credited for sparking the resurgence of the American conservative political movement in the 1960s.

Goldwater rejected the legacy of the New Deal and fought inside the Conservative coalition to defeat the New Deal coalition. He lost the 1964 presidential election by a large margin to incumbent Democrat Lyndon B. Johnson. The Johnson campaign and other critics painted him as a reactionary, while supporters praised his crusades against the federal government, labor unions, and the welfare state. His defeat allowed Lyndon Johnson and the Democrats in Congress to pass the Great Society programs, but the defeat of so many older Republicans in 1964 also cleared the way for a younger generation of American conservatives to mobilize. Goldwater was much less active as a national leader of conservatives after 1964; his supporters mostly rallied behind Ronald Reagan, who became Governor of California in 1967 and President of the United States in 1981.

By the 1980s, the increasing influence of the Christian Right on the Republican Party so conflicted with Goldwater's libertarian views that he became a vocal opponent of the religious right on issues such as abortion and gay rights. Goldwater concentrated on his Senate duties, especially passage of the Goldwater-Nichols Act of 1986.