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. Until 2022, this had been the only election cycle where only one U.S. Senate seat flipped parties.
The 1988 United States Senate elections were elections for the United States Senate. Held on November 8, the 33 seats of Class 1 were contested in regular elections. In spite of the Republican victory by George H. W. Bush in the presidential election, the Democrats gained a net of one seat in the Senate. Seven seats changed parties, with four incumbents being defeated. The Democratic majority in the Senate increased by one to 55–to–45.
The 1986 United States Senate elections were elections for the United States Senate. Held on November 4, in the middle of Ronald Reagan's second presidential term, the 34 seats of Class 3 were contested in regular elections. The Republicans had to defend an unusually large number of freshman Senate incumbents who had been elected on President Ronald Reagan's coattails in 1980. Democrats won a net of eight seats, defeating seven freshman incumbents, picking up two Republican-held open seats, and regaining control of the Senate for the first time since January 1981. This remains the most recent midterm election cycle in which the sitting president's party suffered net losses while still flipping a Senate seat.
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 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 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.
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.
Robert Winthrop Kean was an American Republican Party politician from the state of New Jersey. Kean represented parts of Essex County, New Jersey in the United States House of Representatives from 1939 to 1959. He retired from the House to run for United States Senate in 1958, but was defeated by Harrison A. Williams.
The United States Senate election of 1946 in New Jersey was held on November 5, 1946.
The United States Senate election of 1940 in New Jersey was held on November 5, 1940.
The United States Senate election of 1942 in New Jersey was held on November 3, 1942. Incumbent Democratic Senator William Smathers ran for re-election to a second term, but was defeated by Republican businessman Albert Hawkes.
The United States Senate special election of 1938 in New Jersey was held on November 8, 1938.
The 1944 United States Senate special election in New Jersey was held on November 7, 1944.
The United States Senate election of 1916 in New Jersey was held on November 7, 1916.
The United States Senate election of 1922 in New Jersey was held on November 7, 1922.
The 1924 United States Senate election in New Jersey was held on November 4, 1924. Incumbent Republican Senator Walter Evans Edge was re-elected to a second term in office. He would not complete the term, resigning from office in 1929 to be sworn in as the U.S. Ambassador to France.
The United States Senate election of 1928 in New Jersey was held on November 6, 1928. Incumbent Democratic Senator Edward I. Edwards ran for re-election to a second term in office, but was defeated by Hamilton Fish Kean in a landslide. This was the third of four straight elections to this seat in which the incumbents were defeated.
The 1958 United States Senate election in New Jersey was held on November 4, 1958.
