The 1998 United States Senate elections were held on November 3 and seen as an even contest between the Republican Party and Democratic Party. While the Democrats had to defend more seats up for election, Republican attacks on the morality of President Bill Clinton failed to connect with voters and anticipated Republican gains did not materialize. The Republicans picked up open seats in Ohio and Kentucky and narrowly defeated Democratic incumbent Carol Moseley Braun (Illinois), but these were cancelled out by the Democrats' gain of an open seat in Indiana and defeats of Republican Senators Al D'Amato and Lauch Faircloth. The balance of the Senate remained unchanged at 55–45 in favor of the Republicans. With Democrats gaining five seats in the House of Representatives, this marked the first time since 1934 that the out-of-presidency party failed to gain congressional seats in a mid-term election, and the first time since 1822 that the party not in control of the White House failed to gain seats in the mid-term election of a President's second term. These are the last senate elections that resulted in no net change in the balance of power.
The 1986 United States Senate elections was an election for the United States Senate in the middle of Ronald Reagan's second presidential term. 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 and regaining control of the Senate for the first time since January 1981. The party not controlling the presidency gained seats, as usually occurs in mid-term elections.
The 1982 United States Senate elections were held on November 2, 1982. They were elections for the United States Senate following Republican gains in 1980. A total of four seats changed hands between parties, and the lone independent, Senator Harry Byrd Jr., retired. Democrats made a net gain of one seat in the elections. A special election in 1983 was then held after the winner of Washington's 1982 election died at the beginning of the term.
The 1978 United States Senate elections in the middle of Democratic President Jimmy Carter's term. Thirteen seats changed hands between parties. The Democrats at first lost a net of two seats to the Republicans, and then one more in a special election. Democrats nevertheless retained a 58-41 majority.
The 1976 United States Senate elections was an election for the United States Senate that coincided with Democratic Jimmy Carter's presidential election and the United States Bicentennial celebration. Although almost half of the seats decided in this election changed parties, Carter's narrow victory did not provide coattails for the Democrats, and the balance of the chamber remained the same.
The 1970 United States Senate elections was an election for the United States Senate, taking place 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 1964 United States Senate elections 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 2019, this is the last time either party has had a two-thirds majority in the Senate, which would have hypothetically allowed the Senate Democrats to override a veto, convict and expel certain officials, or invoke cloture without any votes from Republicans. The Senate election 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. As is common in midterm elections, the party in the White House lost seats, but losses this year were more than usual, perhaps due to the high unemployment of the Recession of 1958. The Eisenhower Administration's position on right-to-work issues galvanized labor unions which supported Democrats. The launch of Sputnik may also have been a factor.
The 1956 United States Senate elections were elections for the United States Senate that coincided with the re-election of President Dwight D. Eisenhower. Although the Democrats gained two seats in regular elections, the Republicans gained back two seats in special elections, leaving the party balance of the chamber remained unchanged.
The 1954 United States Senate elections was a midterm election in the first term of Dwight D. Eisenhower's presidency. 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 caucused with them.
The 1950 United States Senate elections occurred in the middle of Harry S. Truman's second term as President. As with most 20th-century second-term mid-terms, the party out of 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 became the first time since 1932 that the Senate Majority Leader lost his seat and the only instance where the majority leader lost 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.
The United States Senate elections of 1936 coincided with the reelection of President Franklin D. Roosevelt. 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, the most lopsided Senate since Reconstruction.
The United States Senate elections of 1926 were elections for the United States Senate that occurred in the middle of Republican President Calvin Coolidge's second term. The Republican majority was reduced by six seats.
The 1948 South Carolina United States Senate election was held on November 2, 1948 to select the U.S. Senator from the state of South Carolina. Incumbent Democratic Senator Burnet R. Maybank won the Democratic primary and defeated Republican challenger J. Bates Gerald in the general election to win another six-year term.
The 1948 United States elections was held on November 2, 1948. The election took place during the beginning stages of the Cold War. Democratic incumbent President Harry S. Truman was elected to a full term, defeating Republican nominee New York Governor Thomas E. Dewey and two erstwhile Democrats. The Republicans, who had just won both the House and the Senate two years earlier, ceded control of both chambers of Congress to the Democrats. Puerto Rico also elected Luis Muñoz Marín of the Popular Democratic Party as its first democratically elected governor.
The 1949 New York state election was held on November 8, 1949, to elect a judge of the New York Court of Appeals and a U.S. Senator.
The 1934 United States Senate election in Missouri was held on November 6, 1934. Incumbent Republican U.S. Senator Roscoe Patterson, first elected in 1928, sought reelection to a second term. He was defeated by the Democratic nominee, future President of the United States Harry Truman.
The 1952 United States elections was held on November 4. The Republicans took control of the presidency and both chambers of Congress for the first time since the Great Depression. The election took place during the Korean War.
Elections to the United States Senate will be held on November 3, 2020, with the 33 Class 2 seats of the Senate being contested in regular elections. The winners will be elected to six-year terms extending from January 3, 2021, until January 3, 2027. Additionally, there will be a special election in Arizona to fill the vacancy created by the death of John McCain in 2018.
