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. This was the first time since 1980 that any party successfully defended all their own seats, and the first time Democrats did so since 1958.
The 1974 United States Senate elections were held on November 5, with the 34 seats of Class 3 contested in regular elections. They occurred in the wake of the Watergate scandal, Richard M. Nixon's resignation from the presidency, and Gerald Ford's subsequent pardon of Nixon. Economic issues, specifically inflation and stagnation, were also a factor that contributed to Republican losses. As an immediate result of the November 1974 elections, Democrats made a net gain of three seats from the Republicans, as they defeated Republican incumbents in Colorado and Kentucky and picked up open seats in Florida and Vermont, while Republicans won the open seat in Nevada. Following the elections, at the beginning of the 94th U.S. Congress, the Democratic caucus controlled 60 seats, and the Republican caucus controlled 38 seats.
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 1968 United States Senate elections were elections for the United States Senate. Held on November 5, the 34 seats of Class 3 were contested in regular elections. They coincided with the presidential election of the same year. The Republicans picked up five net seats in the Senate. This saw Republicans win a Senate seat in Florida for the first time since Reconstruction.
The 1966 United States Senate elections were elections on November 8, 1966, for the United States Senate which occurred midway through the second term of President Lyndon B. Johnson. The 33 seats of Class 2 were contested in regular elections. Special elections were also held to fill vacancies. With divisions in the Democratic base over the Vietnam War, and with the traditional mid-term advantage of the party not holding the presidency, the Republicans took three Democratic seats, thereby breaking Democrats' 2/3rds supermajority. Despite Republican gains, the balance remained overwhelmingly in favor of the Democrats, who retained a 64–36 majority. Democrats were further reduced to 63–37, following the death of Robert F. Kennedy in June 1968.
The 1932 United States Senate elections coincided with Democrat Franklin D. Roosevelt's landslide victory over incumbent Herbert Hoover in the presidential election. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies.
The 1930 United States Senate elections occurred in the middle of Republican President Herbert Hoover's term. The 32 seats of Class 2 were contested in regular elections, and special elections were held to fill vacancies. With the Great Depression beginning to take hold, Republican incumbents became unpopular, and Democrats picked up a net of eight seats, erasing the Republican gains from the previous election cycle, however, Republicans retained control of the chamber. This was the first of four consecutive Senate elections during the Depression in which Democrats made enormous gains, achieving a cumulative pick-up of 34 seats.
The 1948 United States Senate election in Louisiana was held on November 2, 1948. Incumbent Senator Allen J. Ellender was re-elected to a third term in office.
The 1932 United States Senate election in Louisiana was held on November 8, 1932. Incumbent Democratic Senator Edwin Broussard ran for a third term in office, but was defeated in the primary by U.S. Representative John H. Overton.
The 1920 United States Senate election in Louisiana was held on November 2, 1920. Incumbent senator Edward J. Gay did not run for re-election.
The 1956 United States Senate election in Louisiana was held on November 6, 1956. Incumbent Democratic U.S. Senator Russell B. Long won re-election to a third term.
The 1950 United States Senate election in Louisiana was held on November 7, 1950. Incumbent Democratic U.S. Senator Russell B. Long won re-election to a second term.
The 1926 United States Senate election in Louisiana was held on November 2, 1926. Incumbent Democratic Senator Edwin Broussard was elected to a second term in office.
The 1930 United States Senate election in Louisiana was held on November 4, 1930.
The 1966 United States Senate election in Georgia was held on November 8, 1966. Incumbent Democratic Senator Richard Russell Jr. was elected to a seventh term in office.
The 1944 United States Senate election in Louisiana was held on November 7, 1944. Incumbent Democratic Senator John H. Overton was elected to a third term in office.
The 1954 United States Senate election in Louisiana was held on November 2, 1954. Incumbent Senator Allen J. Ellender was re-elected to a fourth term in office.
The 1962 United States Senate election in Louisiana was held on November 6, 1962. Incumbent Democratic Senator Russell Long was elected to a fourth term in office.
The 1966 United States Senate election in Louisiana was held on November 8, 1966. Incumbent Democratic Senator Allen Ellender was elected to a sixth term in office.
The 1968 United States Senate election in Louisiana was held on November 5, 1968. Incumbent Democratic Senator Russell Long was elected to a fifth term in office.
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