The 1990 United States Senate elections were held on Tuesday, November 6, 1990, with the 33 seats of Class 2 contested in regular elections. Special elections were also held to fill vacancies. The Democratic Party increased its majority with a net gain of one seat from the Republican Party. The election cycle took place in the middle of President George H. W. Bush's term, and, as with most other midterm elections, the party not holding the presidency gained seats in Congress.
The 1978 United States Senate elections were held on November 7, in the middle of Democratic President Jimmy Carter's term. The 33 seats of Class 2 were contested in regular elections. Special elections were also held to fill vacancies.
The 1972 United States Senate elections were held on November 7, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of Republican President Richard Nixon. Despite Nixon's landslide victory, Democrats increased their majority by two seats. The Democrats picked up open seats in Kentucky and South Dakota, and defeated four incumbent senators: Gordon Allott of Colorado, J. Caleb Boggs of Delaware, Jack Miller of Iowa, and Margaret Chase Smith of Maine. The Republicans picked up open seats in New Mexico, North Carolina, and Oklahoma, and defeated one incumbent, William B. Spong Jr. of Virginia.
The 1970 United States Senate elections was an election for the United States Senate. It took place on November 3, with the 33 seats of Class 1 contested in regular elections. Special elections were also held to fill vacancies. These races occurred in the middle of Richard Nixon's first term as president. The Democrats lost a net of three seats, while the Republicans and the Conservative Party of New York picked up one net seat each, and former Democrat Harry F. Byrd Jr. was re-elected as an independent.
The 1960 United States Senate elections coincided with the election of John F. Kennedy as president on November 8, 1960. The 33 seats of Class 2 were contested in regular elections. A special election was also held on June 28, 1960, for a mid-term vacancy in North Dakota where Democrats flipped a seat to expand their majority to 66–34. As Majority Leader Lyndon Johnson was elected Vice President, Mike Mansfield became the new majority leader.
The 1958 United States Senate elections were elections for the United States Senate which occurred in the middle of President Dwight D. Eisenhower's second term. Thirty-two seats of Class 1 were contested in regular elections, the new state of Alaska held its first Senate elections for its Class 2 and 3 seats, and two special elections were held to fill vacancies.
The 1956 United States Senate elections were elections for the United States Senate that coincided with the re-election of President Dwight D. Eisenhower. The 32 seats of Class 3 were contested in regular elections, and three special elections were held to fill vacancies. Although Democrats gained two seats in regular elections, the Republicans gained two seats in special elections, leaving the party balance of the chamber unchanged.
The 1954 United States Senate elections was a midterm election in the first term of Dwight D. Eisenhower's presidency. The 32 Senate seats of Class 2 were contested in regular elections, and six special elections were held to fill vacancies. Eisenhower's Republican party lost a net of two seats to the Democratic opposition. This small change was just enough to give Democrats control of the chamber with the support of an Independent who agreed to caucus with them, he later officially joined the party in April 1955.
The 1950 United States Senate elections occurred in the middle of Harry S. Truman's second term as president. The 32 seats of Class 3 were contested in regular elections, and four special elections were held to fill vacancies. As with most 20th-century second-term midterms, the party not holding the presidency made significant gains. The Republican opposition made a net gain of five seats, taking advantage of the Democratic administration's declining popularity during the Cold War and the aftermath of the Recession of 1949. The Democrats held a narrow 49-to-47-seat majority after the election. This was the first time since 1932 that the Senate majority leader lost his seat, and the only instance of the majority leader losing his seat while his party retained the majority.
The 1938 United States Senate elections occurred in the middle of Franklin D. Roosevelt's second term. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies. The Republicans gained eight seats from the Democrats, though this occurred after multiple Democratic gains since the 1932 election, leading to the Democrats retaining a commanding lead over the Republicans with more than two-thirds of the legislative chamber.
Rear Admiral John Geraerdt Crommelin Jr. was a prominent American naval officer and later a frequent political candidate who championed white supremacy.
The 1982 United States Senate election in California took place on November 2, 1982. Incumbent Republican U.S. Senator S. I. Hayakawa decided to retire after one term. Republican Pete Wilson, the Mayor of San Diego, won Hayakawa's open seat over Democratic Governor Jerry Brown and several minor candidates.
The 1968 United States Senate election in Alabama took place on November 5, 1968. Incumbent Democratic U.S. Senator J. Lister Hill retired. He was succeeded by Lieutenant Governor of Alabama James Allen, who won a hotly contested primary over Armistead I. Selden Jr. In the general election, Allen easily defeated Republican Probate Judge Perry O. Hooper Sr. and National Democratic nominee Robert Schwenn.
The United States Senate election in Alabama of 1950 was held on November 7, 1950.
The 1954 United States Senate election in Alabama was held on November 2, 1954.
The 1960 United States Senate election in Alabama was held on November 8, 1960.
The 1962 United States Senate election in Alabama was held on November 6, 1962 to elect one of Alabama's members to the United States Senate. Incumbent Democratic U.S. Senator J. Lister Hill won re-election to his fifth, and last, full term.
The 1966 United States Senate election in Alabama was held on November 8, 1966. Incumbent Senator John Sparkman was re-elected to a fourth full term in office over Republican John Grenier.
The 1956 United States Senate election in Idaho took place on November 6, 1956. Incumbent Republican Senator Herman Welker was defeated for re-election by Democratic nominee Frank Church.
The 1956 United States Senate special election in West Virginia took place on November 6, 1956, to elect a U.S. Senator to complete the unexpired term of Senator Harley M. Kilgore, who died on February 28. 1956. State Tax Commissioner William Laird III was appointed to fill this seat by Governor William C. Marland to fill the vacancy until a special election could be held and assumed office on March 13, 1956.
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