The 1988 United States Senate elections were elections for the United States Senate. Held on November 8, 1988, 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 1 seat in the Senate. 7 seats changed parties, with 4 incumbents being defeated. The Democratic majority in the Senate increased by one to 55–45.
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 1984 United States Senate elections were held on November 6, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of President Ronald Reagan in the presidential election. In spite of the lopsided presidential race, Reagan's Republican Party suffered a net loss of two Senate seats to the Democrats, although it retained control of the Senate with a reduced 53–47 majority.
The 1980 United States Senate elections were held on November 4, coinciding with Ronald Reagan's victory in the presidential election. The 34 Senate seats of Class 3 were contested in regular elections. Reagan's large margin of victory over incumbent Jimmy Carter gave a huge boost to Republican Senate candidates, allowing them to flip 12 Democratic seats and win control of the chamber for the first time since the end of the 83rd Congress in January 1955. This was the first time since 1966 that any party successfully defended all their own seats.
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 1964 United States Senate elections were held on November 3. The 33 seats of Class 1 were contested in regular elections. Special elections were also held to fill vacancies. They coincided with the election of President Lyndon B. Johnson by an overwhelming majority, to a full term. His Democratic Party picked up a net two seats from the Republicans. As of 2023, this was the last time either party has had a two-thirds majority in the Senate, which allowed the Senate Democrats to override a veto, propose constitutional amendments, or convict and expel certain officials without any votes from Senate Republicans. However, internal divisions would have prevented the Democrats from having done so. The Senate election cycle coincided with Democratic gains in the House in the same year.
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 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 help of the Independent who at the start of this Congress in January 1955 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 1946 United States Senate elections were held November 5, 1946, in the middle of Democratic President Harry S. Truman's first term after Roosevelt's passing. The 32 seats of Class 1 were contested in regular elections, and four special elections were held to fill vacancies. The Republicans took control of the Senate by picking up twelve seats, mostly from the Democrats. This was the first time since 1932 that the Republicans had held the Senate, recovering from a low of 16 seats following the 1936 Senate elections.
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 1936 United States Senate elections coincided with the reelection of President Franklin D. Roosevelt. The 32 seats of Class 2 were contested in regular elections, and special elections were held to fill vacancies. The Great Depression continued and voters backed progressive candidates favoring Roosevelt's New Deal in races across the country. The Democrats gained 5 net seats during the election, and in combination with Democratic and Farmer–Labor interim appointments and the defection of George W. Norris from the Republican Party to become independent, the Republicans were reduced to 16 seats. Democrats gained a further two seats due to mid-term vacancies. The Democrats' 77 seats and their 62-seat majority remain their largest in history.
The 1934 United States Senate elections were held in the middle of Democratic President Franklin D. Roosevelt's first term. The 32 seats of Class 1 were contested in regular elections, and special elections were held to fill vacancies. During the Great Depression, voters strongly backed Roosevelt's New Deal and his allies in the Senate, with Democrats picking up a net of nine seats, giving them a supermajority. Republicans later lost three more seats due to mid-term vacancies ; however, a Democrat in Iowa died and the seat remained vacant until the next election. The Democrats entered the next election with a 70-22-2-1 majority.
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 1932 United States House of Representatives elections were elections for the United States House of Representatives to elect members to serve in the 73rd United States Congress. They were held for the most part on November 8, 1932, while Maine held theirs on September 12. They coincided with the landslide election of President Franklin D. Roosevelt.
The 1908–09 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were primarily chosen by state legislatures. Senators were elected over a wide range of time throughout 1906 and 1907, and a seat may have been filled months late or remained vacant due to legislative deadlock. However, some states had already begun direct elections during this time. Oregon pioneered direct election and experimented with different measures over several years until it succeeded in 1907. Soon after, Nebraska followed suit and laid the foundation for other states to adopt measures reflecting the people's will. By 1912, as many as 29 states elected senators either as nominees of their party's primary or in conjunction with a general election.
The 1952 United States Senate election in Maryland was held on November 4, 1952.
The 1958 United States Senate elections in Alaska were held November 25, 1958. The elections were held in anticipation of Alaska's admission as the forty-ninth state in the union, effective January 3, 1959. The state held two simultaneous elections to determine their first senators.
Democrat William Proxmire won a special election to fill the vacancy created by the death of Senator Joseph R. McCarthy (R-WI). Also, Price Daniel (D-TX) left the Senate to become governor of Texas, and Democrat Ralph Yarborough won a special election for that Senate seat. The Democrats thus made a net gain of one seat. However, Congress was out of session at the time of the Democratic gain in Wisconsin, and the Republicans gained a Democratic-held seat only weeks after the next session started, when Republican John D. Hoblitzell Jr. was appointed to fill the vacancy created by the death of Senator Matthew M. Neely (D-WV).
