2018 United States Senate elections

2018 United States Senate elections

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35 of the 100 seats in the United States Senate 51 seats needed for a majority
Majority party Minority party   Leader Mitch McConnell Chuck Schumer Party Republican Democratic Leader since January 3, 2007 January 3, 2017 Leader's seat Kentucky New York Seats before 51 47 Seats after 53 45 Seat change 2 2 Popular vote 34,687,875 52,224,867[a][b] Percentage 38.7% 58.2% Seats up 9 24 Races won 11 22   Third party   Party Independent Seats before 2[c] Seats after 2 Seat change Popular vote 808,370[d] Percentage 0.9% Seats up 2 Races won 2
Results of the elections:      Democratic gain      Republican gain      Democratic hold      Republican hold      Independent hold      No election Rectangular inset (Minn. & Miss.): both seats up for election
Majority Leader before election Mitch McConnell Republican Elected Majority Leader Mitch McConnell Republican

The 2018 United States Senate elections were held on November 6, 2018. Among the 100 seats, the 33 of Class 1 were contested in regular elections while two others were contested in special elections due to Senate vacancies in Minnesota and Mississippi. The regular election winners were elected to six-year terms running from January 3, 2019, to January 3, 2025. Senate Democrats had 26 seats up for election (including the seats of two Independents who caucus with them), while Senate Republicans had nine seats up for election.

To maintain their working majority of 50 senators and their party's vice president's tie-breaking vote, Republicans could only afford a net loss of one seat in these elections. The Republicans had a 52–48 majority after the 2016 elections, but they lost a seat in Alabama after Jeff Sessions resigned to become U.S. attorney general and Doug Jones, a Democrat, won in the subsequent special election. Three Republican-held seats were open as a result of retirements in Tennessee, Utah, and Arizona. Although every Democratic incumbent ran for re-election, Democrats faced an extremely unfavorable map, defending 26 seats, of which 10 were in states won by Donald Trump in the 2016 presidential election, and five of those where Trump had won by more than 10%. Republicans, however, only had to defend nine seats, of which only one was in a state won by Hillary Clinton in 2016.

The Republicans increased their majority by defeating Democratic incumbents in Florida, Indiana, Missouri, and North Dakota, and holding the open seats in Tennessee and Utah. Democrats won 2 Republican-held seats, defeating an incumbent in Nevada and winning the open seat in Arizona. This was the first time Republicans gained Class 1 Senate seats since 1994.

The results for this election cycle were the only significant gains made by the Republicans in what was otherwise characterized as a "blue wave" election. The Republican gains in the Senate and the Democratic gains in the House marked the first midterm election cycle since 1970 in which the president's party made net gains in one chamber of Congress while suffering net losses in the other,^[3] which also occurred in 1914, 1962, and 2022. This was also the first midterm election cycle since 2002 in which any incumbents of the non-presidential party lost re-election. The number of defeated non-presidential party incumbents (4) was the most since the 1934 mid-terms.^[4] To date, this remains the last time that Democrats won a Senate election in Montana, Ohio, and West Virginia.

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