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 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 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 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 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.
Robert Blackford Duncan was an American politician from the state of Oregon. A Democrat, he served multiple terms in the Oregon Legislative Assembly and as a U.S. congressman from Oregon. In the Oregon House of Representatives he served as speaker for four years, and in the U.S. House he represented two different districts. The Illinois native and World War II veteran ran three unsuccessful campaigns to be elected to the U.S. Senate.
Maurine Neuberger-Solomon, best known as Maurine Neuberger was an American politician who served as a United States senator for the State of Oregon from November 1960 to January 1967. She was the fourth woman elected to the United States Senate and the tenth woman to serve in the body. She and her husband, Richard L. Neuberger, are regarded as the U.S. Senate's first husband-and-wife legislative team. To date, she is the only woman elected to the U.S. Senate from Oregon.
Richard Lewis Neuberger was an American journalist, author, and politician during the middle of the 20th century. A native of Oregon, he wrote for The New York Times before and after a stint in the U.S. Army during World War II. A Democrat, he entered politics in his home state by winning a seat in the Oregon House of Representatives and later was elected to the United States Senate. His widow, Maurine Brown Neuberger, won his Senate seat after his death.
Hall Stoner Lusk was an American jurist in the state of Oregon. A native of the District of Columbia, he became a judge in Oregon, serving in both the Oregon circuit courts and later on the Oregon Supreme Court, including time as its chief justice. A Democrat, he was appointed to the United States Senate for eight months in 1960 after the death of sitting Senator Richard L. Neuberger.
Monroe Mark Sweetland was an American politician in the state of Oregon. A native of the state, he served in both houses of the Oregon Legislative Assembly starting in 1953 for a total of ten years. A Democrat, he also twice ran and lost bids to serve as the Oregon Secretary of State and was a Democratic National Committeeman. Sweetland later served on the staff of the National Education Association, supporting passage of the Bilingual Education Act of 1968.
The 1996 United States Senate election in Oregon was held on November 5, 1996. Incumbent Republican United States Senator Mark Hatfield decided to retire after thirty years in the Senate. Oregon State Senate President Gordon H. Smith, who had run for the Senate earlier that year, won the Republican primary, while businessman Tom Bruggere won a contested Democratic primary. The contest between Smith and Bruggere was one of the toughest that year, but ultimately, Smith was able to keep the seat in the Republican column and defeated Bruggere by a narrow margin. This is the last time that a Senate candidate was elected to the United States Senate in Oregon at the same time that a presidential candidate of the opposite party won Oregon.
The 1990 Oregon United States Senate election was held on November 6, 1990, to select the U.S. Senator from the state of Oregon. Republican candidate Mark Hatfield was re-elected to a fifth term, defeating Democratic businessman Harry Lonsdale.
The 1966 Oregon United States Senate election was held on November 6, 1966 to select the U.S. Senator from the state of Oregon. Incumbent Senator Maurine Brown Neuberger did not seek re-election. Held during the escalation of United States involvement of the Vietnam War, the race was between Republican candidate and incumbent Governor of Oregon Mark Hatfield, who opposed the war, and Democratic congressman Robert B. Duncan, who supported the war. In an unusual move, Oregon's other Senator, Democrat Wayne Morse, who also opposed the war, crossed party lines to endorse Hatfield, who won in a close election, his first of five terms in the United States Senate.
The 1960 United States Senate election in Louisiana took place on November 8, 1960. Incumbent Democratic Senator Allen J. Ellender won re-election to a fifth term.
The 1960 United States Senate election in New Mexico took place on November 8, 1960. Incumbent Democratic Senator Clinton Anderson won re-election to a third term.
The 1962 United States Senate election in Kansas was held on November 6, 1962. Incumbent Republican Senator Frank Carlson was re-elected to a third term in office over Democratic nominee Ken Smith.
The 1962 United States Senate election in Florida took place on November 6, 1962. Incumbent Democratic Senator George Smathers won re-election to a third term. As of 2023, this is the last time that a winning United States Senate candidate carried all counties in Florida for the Class 3 Senate seat from Florida and the last time that a winning United States Senate candidate carried all counties in Florida for a Senate seat from Florida until 1994.
The 1972 United States Senate election in Oregon took place on November 7, 1972. Incumbent Republican Senator Mark Hatfield was re-elected to a second term in office, defeating Democrat Wayne Morse.
The 1978 United States Senate election in Oregon took place on November 7, 1978. Incumbent Republican Senator Mark Hatfield was re-elected to a third term in office, defeating Democrat Vernon Cook.
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.
