How midterm elections have changed Congress since 1946

Editor’s Note: This post ran originally On Nov. 6, 2018 and has been updated to reflect the results of the 2026 midterm elections.

This year, Americans headed to the polls for midterm elections, where the entire House and 35 Senate seats were up for grabs. So how have these elections panned out in the modern era?

Since 1946, when Republicans ended a 14-year period of total Democratic control in Congress, midterm elections have been mostly contested starting in the Reagan era. Between 1946 and 1954, both parties swapped control of Congress. However, starting in 1955, the Democrats had majorities in both houses of Congress after every congressional election until the 1980 Reagan Revolution.

The Republicans grabbed back the Senate for the first six years of the Reagan administration, while the Democrats retained the House. Since 1988, in 20 Congressional elections, the Democrats have gained or retained full control of the House and Senate seven times, including after the 2026 election, while the Republicans have gained or retained full control of Congress eight times. (After the 2000 election, the Democrats gained a deciding vote in the Senate after a Republican became an Independent in May 2001.)

After three elections, 1994, 2006 and 2026, both the House and the Senate changed control.

In the past five midterm elections, the Republicans have held control of the Senate twice after the elections of 2018 and 2024. The Democrats held control three times. After the 2020 election, the GOP initially had a majority until run-off elections concluded on Jan. 20, 2021. Then two independents caucused with 48 Democrats to split the chamber 50-50. The vice president had the tie-breaking vote. The Democrats won the Senate in the 2022 and 2026 elections.

In the House, the Democrats have controlled the House three times after elections (2018, 2020 and 2026), with the Republicans holding the majority after the 2022 and 2024 elections. In seven cases, a party had full control of Congress and the White House. In six cases, full control happened after a presidential election year (1992, 2008, 2016, 2020, and 2024). After the 2000 election, the Republicans had the “trifecta” for five months. In the next election in 2002, the GOP regained full control of Congress.

For official historical results, you can go to the House's official page at: https://history.house.gov/Institution/Party-Divisions/Party-Divisions/

and the Senate's official page at: https://www.senate.gov/history/partydiv.htm

Congressional Election Control Since 1998

* Took control after run-off elections

Post-World II Era Midterms

1946

The Republicans take control of the House and Senate, ending 14 years of a Democratic majority in both chambers that started with Franklin D. Roosevelt’s election in 1932.

1950

The Democrats keep control of both chambers, which they took back in the 1948 general election.

1954 to 1980

The Democrats take back the House and Senate, which they lost in the 1952 general election that saw Dwight Eisenhower elected President. The Democrats control the House and Senate in 13 consecutive elections, including six midterms.

1982

The Republicans keep control of the Senate gained in 1980, while the Democrats keep control of the House.

1986

The Democrats get back control of the Senate, while the Democrats keep control of the House.

1990

The Democrats retain control the House and Senate.

1994

The Republicans gain back the Senate and House.

1998

The Republicans keep the Senate and House for President Bill Clinton’s last two years in office.

2002

The Republicans get back the Senate and keep the House in the first congressional election after 9/11.

2006

The Democrats win back the House and gain control of the Senate thanks to two independent Senators who vote with the Democrats.

2010

In the Tea Party election, the Republicans get the House back by picking up 64 seats in the midterm election. The Democrats retain the Senate.

2014

The Republicans pick up nine Senate seats to win a total majority in Congress.

2016

The Republicans retain their majorities in the House and Senate, but the Democrats pick up 6 House seats.

2018

The Democrats win back the House by picking up 41 seats while the Republicans retain the Senate and gain one seat.

2020

The Democrats keep control of the House and gain the Senate. In the Senate, the GOP controls until January run-off elections. Then two independents caucus with the Democrats to split the chamber 50-50. The vice president has the tie-breaking vote.

2022

The Democrats maintain Senate control as three independents caucus with the party. The Republicans gain back the House after picking up 10 seats.

2024

The Republicans gain full control of the House and Senate, maintaining a 5-seat advantage in the House, and holding 53 seats in the Senate.

2026

The Democrats take full control the House and Senate. A projected 251 or more seats in the House is the most by any party since 2008.

Scott Bomboy is the editor in chief of the National Constitution Center.