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.

This is one of only five occasions where ten or more Senate seats changed hands in an election, with the others being in 1920, 1932, 1946, and 1958. This is the earliest Senate election with a senator who is still serving, that being Chuck Grassley of Iowa.

This was the largest Senate swing since 1958 and the largest Republican gain since 1946, when the Republicans also picked up 12 seats. This was also the last time the Senate changed hands in a presidential election year until 2020 when Democrats won control, the last time the Republicans gained control of the Senate in a presidential election year until 2024, the last time Maryland elected a Republican to the Senate, and the last time where the Republicans made net gains in three or more election cycles in a row, having last experienced net losses in the Senate in 1974 (which also involved the Class 3 Senate seats).

Results summary + ↓ 46 1 53 Democratic I Republican

Parties Total Democratic Republican Independent Libertarian Other Last elections (1978)Before these elections 58 41 1 0 0 100 Not up 34 31 1 0 0 66 Up 24 10 0 — — 34 Incumbent retired 2 3 — — — 5 2 3 — — — 5 0 0 — — — 0 Result 2 3 — — — 5 Incumbent ran 22 7 — — — 29 10 6 — — — 16 9 Democrats replaced by 9 Republicans — — — 9 0 1 — — — 1 3 Democrats replaced by 3 Republicans — — — 3 Result 10 19 0 — — 29 Total elected 12 22 0 0 0 34 Net gain/loss 12 12 12 Nationwide vote 30,699,463 26,597,169 112,242 401,077 1,658,979 59,468,930 Share 51.62% 44.73% 0.19% 0.67% 2.79% 100% Result 46 53 1 0 0 100 Source: Office of the Clerk

Change in composition Before the elections D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D Majority → D R I D D D D D D D R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R

After the elections D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D I R R R Majority → R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R Key D Democratic R Republican I Independent

Gains, losses, and holds Retirements Three Republicans and two Democrats retired instead of seeking re-election.

StateSenatorReplaced by Connecticut Illinois North Dakota Oklahoma Pennsylvania

Defeats One Republican and twelve Democrats sought re-election but lost in the primary or general election.

StateSenatorReplaced by Alabama (lost primary) Alaska (lost primary) Florida (lost primary) Georgia Idaho Indiana Iowa New Hampshire New York (lost primary) North Carolina South Dakota Washington Wisconsin

Post-election changes One Democrat resigned on April 12, 1982, and was later replaced by a Republican appointee.

StateSenatorReplaced by New Jersey(Class 1)

Race summary Special elections There were no special elections in 1980.

Elections leading to the next Congress In these general elections, the winners were elected for the term beginning January 3, 1981; ordered by state.

All of the elections involved the Class 3 seats.

State Incumbent Results Candidates Senator Party Electoral history Alabama Democratic 1978 Incumbent lost renomination.Republican gain.Incumbent resigned January 2, 1981 to give successor advantageous seniority.Winner appointed the same day. Alaska Democratic 19681974 Incumbent lost renomination.Republican gain. Arizona Republican 195219581964 19681974 Incumbent re-elected. Arkansas Democratic 1974 Incumbent re-elected. California Democratic 19681974 Incumbent re-elected. Colorado Democratic 1974 Incumbent re-elected. Connecticut Democratic 196219681974 Incumbent retired.Democratic hold. Florida Democratic 1974 Incumbent lost renomination.Republican gain.Incumbent resigned December 31, 1980 to give successor preferential seniority.Winner appointed January 1, 1981. Georgia Democratic 1956196219681974 Incumbent lost re-election.Republican gain. Hawaii Democratic 196219681974 Incumbent re-elected. Idaho Democratic 1956196219681974 Incumbent lost re-election.Republican gain. Illinois Democratic 1970 1974 Incumbent retired.Democratic hold. Indiana Democratic 196219681974 Incumbent lost re-election.Republican gain. Iowa Democratic 1974 Incumbent lost re-election.Republican gain. Kansas Republican 19681974 Incumbent re-elected. Kentucky Democratic 1974 Incumbent re-elected. Louisiana Democratic 1948 19501956196219681974 Incumbent re-elected. Maryland Republican 19681974 Incumbent re-elected. Missouri Democratic 19681974 Incumbent re-elected. Nevada Republican 1974 Incumbent re-elected. New Hampshire Democratic 1975 Incumbent lost re-election.Republican gain.Incumbent resigned December 29, 1980 to give successor preferential seniority.Winner appointed December 30, 1980. New York Republican 1956196219681974 Incumbent lost renomination, ran as the Liberal nominee, and lost re-election.Republican hold. North Carolina Democratic 1974 Incumbent lost re-election.Republican gain. North Dakota Republican 1945 1946 19501956196219681974 Incumbent retired.Republican hold. Ohio Democratic 19741974 Incumbent re-elected. Oklahoma Republican 19681974 Incumbent retired.Republican hold. Oregon Republican 19681974 Incumbent re-elected. Pennsylvania Republican 19681974 Incumbent retired.Republican hold. South Carolina Democratic 1966 19681974 Incumbent re-elected. South Dakota Democratic 196219681974 Incumbent lost re-election.Republican gain. Utah Republican 1974 Incumbent re-elected. Vermont Democratic 1974 Incumbent re-elected. Washington Democratic 19441944 19501956196219681974 Incumbent lost re-election.Republican gain. Wisconsin Democratic 196219681974 Incumbent lost re-election.Republican gain.

Closest races

In nineteen races the margin of victory was under 10%.

State Party of winner Margin North Carolina Republican (flip) 0.58% Idaho Republican (flip) 0.97% Arizona Republican 1.08% Vermont Democratic 1.32% New York Republican 1.34% Colorado Democratic 1.64% Georgia Republican (flip) 1.74% Wisconsin Republican (flip) 1.85% Pennsylvania Republican 2.44% Alabama Republican (flip) 3.10% Florida Republican (flip) 3.32% New Hampshire Republican (flip) 4.29% Missouri Democratic 4.33% Indiana Republican (flip) 7.58% Alaska Republican (flip) 7.75% Iowa Republican (flip) 7.95% Oregon Republican 8.10% Washington Republican (flip) 8.35% Oklahoma Republican 9.92%

Alabama

Incumbent Democrat Donald Stewart decided to run for his first full term, but was defeated in the primary. In November, Republican Jeremiah Denton defeated Democrat Jim Folsom, public service commissioner.

Alaska

Incumbent Democrat Mike Gravel ran for a third term, but lost in the Democratic primary to Clark Gruening, a former state representative who was the grandson of Ernest Gruening, whom Gravel had defeated twelve years prior in an election for the same seat. Gruening later went on to lose the general election to Republican nominee Frank Murkowski, a banker.

After the loss of Gravel's seat, no Alaska Democrat would win a congressional race again until Mark Begich's narrow, protracted triumph in Alaska's 2008 Senate election.

First elected in 1968, by 1980, two-term Democratic incumbent Mike Gravel had become noted for a filibuster that attempted to end the draft during the Vietnam War and for including the full text of the Pentagon Papers in the Congressional Record.

Gravel faced a challenging bid for re-election, complicated by the fact that his triumph over Ernest Gruening years prior had made him a pariah in the Alaska Democratic Party. Though Gravel had campaigned to be selected as George McGovern's running mate in the 1972 U.S. presidential election and had easily won re-election to the Senate in 1974, he had never established a strong political base in Alaska.Robert KC Johnson, "Not Many Senators Have Found Themselves in Joe Lieberman's Predicament", History News Network, August 7, 2006. Accessed July 7, 2007.

The passage of a controversial land bill earlier in the year, as opposed to a compromise bill worked out by fellow senator Ted Stevens that failed thanks to Gravel two years prior, further harmed his re-election bid.Alex Koppelman, "Don't worry, be Mike Gravel" , Salon.com, May 7, 2007. Accessed July 4, 2007. A group of Democrats, including future governor Steve Cowper, campaigned against Gravel on the land bill issue.Wallace Turner, "Side Issues Figure in Tricky Alaska Primary", The New York Times, July 6, 1982. Accessed July 7, 2007.

The sources of Gravel's campaign funds, some of which came from political action committees outside the state, also became an issue in the contest. Another factor may have been Alaska's blanket primary system, which allows unlimited cross-over voting across parties and from its large unaffiliated electorate; Republicans believed Gruening would be an easier candidate to defeat in the general election. The blanket primary had first been used in the 1968 election, and was something Gravel himself was able to capitalize upon in his 1968 campaign.

Gravel would later comment that, by the time of his primary defeat, he had alienated "almost every constituency in Alaska." In the August 26, 1980 primary, Gruening defeated Gravel by 11 percentage points.

Arizona

Incumbent Republican Barry Goldwater decided to run for reelection to a third consecutive term, after returning to the U.S. Senate in 1968 following his failed presidential run in 1964 against Lyndon B. Johnson. Goldwater defeated Democratic Party nominee Bill Schulz in the general election, but only by a narrow margin, which later caused Goldwater to decide against running for reelection to a fourth consecutive term.

Arkansas

Incumbent Democrat Dale Bumpers won re-election to a second term over real estate broker William Clark.

California

Incumbent Democrat Alan Cranston easily won re-election to a third term over Paul Gann, political activist, even as the state's former Republican governor, Ronald Reagan, claimed a landslide victory in the presidential election.

Colorado

Incumbent Democrat Gary Hart won re-election to a second term over Mary Estill Buchanan, Colorado secretary of state.

Connecticut

Incumbent Democrat Abraham Ribicoff decided to retire. Democrat Chris Dodd won the open seat over James Buckley, former U.S. senator from New York.

Florida

Incumbent Democrat Richard Stone decided to run for re-election to a second term, but was defeated in the Democratic primary election by Bill Gunter. Republican Paula Hawkins won the open seat.

Stone, a freshman senator, had a reputation for changing his mind. In 1980, the AFL–CIO actively campaigned against him, and Stone was deemed vulnerable in his re-election bid. Six Democrats entered the race for Stone's seat, including his 1974 runoff opponent Bill Gunter, who was Florida state treasurer/insurance commissioner in 1980. As was the case in 1974, Stone and Gunter were forced into a runoff, but, unlike in 1974, Gunter won the nomination.

Georgia

Incumbent Democrat and former Governor of Georgia Herman Talmadge decided to run for re-election to a fifth term, but lost a close race to Mack Mattingly, chairman of the Georgia Republican Party. 1980 resulted in a landslide election for Republicans that would come to be known as the Reagan Revolution.

Hawaii

Incumbent Democrat Daniel Inouye was re-elected to a fourth term, defeating Republican Cooper Brown.

Idaho