The 2012 United States Senate elections were held on November 6, 2012, with 33 of the 100 seats in the Senate, all Class 1 seats, being contested in regular elections whose winners would serve six-year terms beginning January 3, 2013, with the 113th Congress. Democrats had 21 seats up for election, plus 1 Independent and 1 Independent Democrat, while the Republicans had only 10 seats up for election. The presidential election, elections to the House of Representatives, elections for governors in 14 states and territories, and many state and local elections were also held on the same day.

Quick Facts 33 of the 100 seats in the United States Senate 51 seats needed for a majority, Majority party ...

2012 United States Senate elections

← 2010 November 6, 2012 2014 →
2013 (MA, NJ) →
33 of the 100 seats in the United States Senate 51 seats needed for a majority
Majority party Minority party   Leader Harry Reid Mitch McConnell Party Democratic Republican Leader's seat Nevada Kentucky Seats before 51 47 Seats after 53 45 Seat change 2 2 Popular vote 49,988,282[1] 39,128,301[1] Percentage 53.4% 41.8% Seats up 21 10 Races won 23 8   Third party   Party Independent Seats before 2[lower-alpha 1] Seats after 2[lower-alpha 2] Seat change Popular vote 961,284[1] Percentage 1.0% Seats up 2 Races won 2
Results of the elections:      Democratic gain      Republican gain      Independent gain      Democratic hold      Republican hold      Independent hold      No election
Majority Leader before election Harry Reid Democratic Elected Majority Leader Harry Reid Democratic

Close

The Democrats gained Republican-held seats in Massachusetts and Indiana and one from an Independent Democrat in Connecticut, leaving them with a total of 53 seats. Additionally, they held open seats in Hawaii, New Mexico, North Dakota, Virginia, and Wisconsin. The Republicans, despite losing two of their seats, picked up an open seat in Nebraska and retained open seats in Arizona and Texas, ending with a total of 45 seats. The Independents retained a seat in Vermont and gained an additional seat from the Republicans in Maine, bringing their total to two seats. Both Independents would caucus with the Democrats, forming a majority caucus with a combined total of 55 seats.

As of 2023^[update], this was the last time the Democrats won seats in Florida, Indiana, Missouri, and North Dakota; and at least one seat in a state that was lost by the Democratic candidate in the concurrent presidential election. It was also the last time the Republican Party won a seat in Nevada. The Democrats would not win control of the Senate again until 2020^{[lower-alpha 3]} and would not win an outright majority again until 2022.

Additionally, this was the first time since 1936 that a two-term Democratic presidential candidate had Senate coattails on both occasions. (Although Franklin Roosevelt won third and fourth terms in 1940 and 1944 respectively, he lost Senate seats on both occasions.) This was also the first time since 1964 in which either party had to defend more than two-thirds of the Senate seats up for grabs but managed to make net gains.^[2][3] As of 2023^[update], this is the last election cycle in which an incumbent senator lost renomination, the last election cycle in which there were no runoff elections, the last time a party flipped a Senate seat while failing to carry the state in the presidential election, and the last time a party flipped a Senate seat in a state whose other seat was flipped by the opposition party in the previous election cycle.

Shading indicates party with largest share of that line.

More information Parties, Total ...

Parties									Total
		Democratic	Republican	Independent	Libertarian	Independence	Green	Others
Before these elections		51	47	2	—	—	—	—	100
Not up		30	37	—	—	—	—	—	67
	Class 2 (2008→2014)	20	13	—	—	—	—	—	33
	Class 3 (2010→2016)	10	24	—	—	—	—	—	34
Up		21	10	2	—	—	—	—	33
	Class 1	21	10	2	—	—	—	—	33
Incumbent retired		6	3	1	—	—	—	—	10
	Held by same party	5	2	—	—	—	—	—	7
	Replaced by other party	1 Independent replaced by 1 Democrat 1 Republican replaced by 1 Independent 1 Democrat replaced by 1 Republican			—	—	—	—	3
	Result	6	3	1	—	—	—	—	10
Incumbent ran		15	7[lower-alpha 4][lower-alpha 5]	1	—	—	—	—	23
	Won re-election	15	5	1	—	—	—	—	21
	Lost re-election	1 Republican replaced by 1 Democrat		—	—	—	—	—	1
	Lost renomination but held by same party	—	—	—	—	—	—	—
	Lost renomination and party lost	1 Republican replaced by 1 Democrat		—	—	—	—	—	1
	Result	17	5	1	—	—	—	—	23
Total elected		23	8	2	—	—	—	—	33
Net gain/loss		2	2		—	—	—	—	2
Nationwide vote		49,988,282	39,128,301	961,284	956,745	211,794	195,200	2,119,714	93,561,320[1]
	Share	53.43%	41.82%	1.03%	1.02%	0.23%	0.21%	2.27%	100%
Result		53	45	2	—	—	—	—	100
End of this Congress		51	47	2	—	—	—	—	100

Close

Elections with a margin less than 10.0%.

The table below gives an overview of some final predictions of the November general elections by several well-known institutes and people. While there were very few mistakes (predictions in the wrong direction; essentially only Montana and North Dakota, by both Sabato's Crystal Ball and FiveThirtyEight), FiveThirtyEight and Princeton Election Consortium had 2-4 races in the Lean categories and no tossups, whereas all other sources had at least eleven races in the middle three categories, and in particular many Tossup races.

Quick Facts Turnout, Nominee ...

Arizona election

← 2006 2018 →
Turnout	52.9% (voting eligible)[25]
Nominee Jeff Flake Richard Carmona Party Republican Democratic Popular vote 1,104,457 1,036,542 Percentage 49.2% 46.2%
Flake:      40–50%      50–60%      60–70% Carmona:      50–60%      60–70%
U.S. senator before election Jon Kyl Republican Elected U.S. senator Jeff Flake Republican

Close

Three-term incumbent and Senate Minority Whip Republican Jon Kyl, who was re-elected in 2006 with 53% of the vote, announced he would not seek a fourth term in 2012.^[4][26] Republican representative Jeff Flake^[27] won the August 28 primary with 69.1% of the vote, against three contenders, including real estate investor Wil Cardon^[28] who polled 21.2%. On the Democratic side, former U.S. Surgeon General Richard Carmona^[29] won the primary election, which was held August 28, 2012.

Preliminary general election results showed Flake leading 49.7%-45.7%, but 439,961 early votes had yet to be counted.^[31] The official results, as tabulated by the secretary of state, showed a slightly smaller win for Flake. Flake won the election with 49.7% of the vote against Carmona's 46.2% and Victor's 4.6%.^[32]

Quick Facts Turnout, Nominee ...

California election

← 2006 2018 →
Turnout	55.2% (voting eligible)[25]
Nominee Dianne Feinstein Elizabeth Emken Party Democratic Republican Popular vote 7,864,624 4,713,887 Percentage 62.5% 37.5%
Feinstein:      50–60%      60–70%      70–80%      80–90% Emken:      50–60%      60–70%      70–80%
U.S. senator before election Dianne Feinstein Democratic Elected U.S. senator Dianne Feinstein Democratic

Close

Incumbent Democrat Dianne Feinstein was re-elected. The primary election on June 5 took place under California's new blanket primary, where all candidates appear on the same ballot, regardless of party. In the primary, voters voted for any candidate listed, or write-in any other candidate. The top two finishers — regardless of party — advanced to the general election in November, even if a candidate managed to receive a majority of the votes cast in the June primary. In the primary, less than 15% of the total 2010 census population voted. Incumbent Democrat Dianne Feinstein finished first in the blanket primary with 49.5% of the vote. The second-place finisher was Republican candidate and autism activist Elizabeth Emken, who won 12.7% of the vote.

Feinstein and Emken contested the general election on November 6, with Feinstein winning re-election in a landslide, by 62.5% to 37.5%. Feinstein's 7.86 million votes set the all-time record for the most votes cast for one candidate in one state in one election, beating senator Barbara Boxer's 6.96 million votes in 2004. This record was held until the 2016 presidential election in California, when Hillary Clinton won 8.75 million votes in the state.

Quick Facts Turnout, Nominee ...

Connecticut election

← 2006 2018 →
Turnout	60.9% (voting eligible)[25]
Nominee Chris Murphy Linda McMahon Party Democratic Republican Popular vote 815,077 637,857 Percentage 55.1% 43.3%
County results Municipality results Murphy:      40–50%      50–60%      60–70%      70–80%      80–90% McMahon:      40–50%      50–60%      60–70%
U.S. senator before election Joe Lieberman Independent Elected U.S. senator Chris Murphy Democratic

Close

Incumbent Joe Lieberman, an independent who caucused with the Democratic Party, retired instead of running for re-election to a fifth term.^[34] Republican businesswoman Linda McMahon faced Democratic representative Chris Murphy in the general election and lost, marking two defeats in as many years.^[35]

In the 2006 election, incumbent Joe Lieberman was defeated in the Democratic primary by businessman Ned Lamont and formed his own party, Connecticut for Lieberman, winning re-election. Lieberman promised to remain in the Senate Democratic Caucus, but had clashed with Democrats on many significant issues, including his endorsement of Republican 2008 presidential nominee John McCain over Barack Obama.^[36] As a result, Lieberman's poll numbers among Democrats had dropped significantly.^[37][38]

Connecticut Attorney General Richard Blumenthal was reportedly considering a run against Lieberman,^[39] but instead ran for and won Connecticut's other Senate seat in 2010 after U.S. senator Christopher Dodd announced his retirement.^[40]

Lieberman had publicly floated the possibility of running as a Democrat,^[41] Republican,^[42] or an independent.^[43] However, he announced on January 19, 2011, that he would not run for another term.^[34]

Susan Bysiewicz was the first to declare herself as a candidate.^[44] However, by March 2011 Chris Murphy had raised over $1 million, while Bysiewicz had raised only $500,000. Murphy represented Connecticut's 5th congressional district, which was considered Republican-leaning, and he promoted himself as the most electable candidate against a Republican challenger. Bysiewicz, the former Secretary of the State of Connecticut, enjoyed high name recognition while a statewide officeholder, and had a formidable face-off with Murphy. William Tong, a state representative, joined the race touting his biography as the son of Chinese immigrants working at a Chinese restaurant.^[45] In January East Hartford resident Matthew John Oakes announced his candidacy. Oakes pointed to his real life experience being a disabled American, victim of crime, civil rights activist, growing up in the inner-city and being a political outsider for his candidacy.^[46]

Wide speculation continued on Linda McMahon, who had a widely publicized race for senator in 2010. She lost the election decisively, but had strong finances and a well-established political organization.^[45] McMahon met with her former campaign consultant to review her 2010 results, and said she was leaning towards running. She planned to make a decision regarding another run after the start of 2012. Congressman Chris Shays joined in August 2011, promoting his involvement in Iraq and Afghanistan's military contracting.^[47] Shays campaign also gained traction from a series of independent polls showing him beating or in dead heat with the top Democratic contenders in the general election, while those same polls showed McMahon losing handily to each of the top Democratic contenders.^[48] The Shays campaign has quickly capitalized on these polls, arguing for the former Congressman's electability while questioning McMahon's electability due to her loss in an open Senate seat contest in 2010 by a large margin despite spending $50 million of her own money, and also citing both her high unfavorable numbers among voters and her poor fundraising.^[49]

In July 2012, Shays declared that he would not support McMahon if she won the primary. He said that he had "never run against an opponent that I have respected less—ever—and there are a lot of candidates I have run against," adding that "I do not believe that Linda McMahon has spent the time, the energy to determine what [being] a senator really means." He also said that during the last debate he had with McMahon, "I thought she was embarrassingly clueless" and that "I think she is a terrible candidate and I think she would make a terrible senator." Although he said he would not support Chris Murphy, he expected him to win the Democratic nomination and the general election.^[50]

In September 2012, the records of the McMahons' 1976 bankruptcy and specifics of nearly $1 million unpaid debts from the proceeding were published.^[51] In days the candidate and her husband announced the "intention to reimburse all private individual creditors that can be located".^[52]

Note: Murphy also appeared on the line of the Connecticut Working Families Party and received 37,553 votes on it. His Working Families and Democratic votes have been aggregated together on this table.

Quick Facts Turnout, Nominee ...

Delaware election

← 2006 2018 →
Turnout	62.7% (voting eligible)[25]
Nominee Tom Carper Kevin Wade Party Democratic Republican Popular vote 265,374 115,694 Percentage 66.4% 29.0%
Carper:      40–50%      50–60%      60–70%      70–80%
U.S. senator before election Tom Carper Democratic Elected U.S. senator Tom Carper Democratic

Close

Incumbent Democrat Tom Carper won re-election to a third term.

Note: The ±% column reflects the change in total number of votes won by each party from the previous election. Neither the vote shares nor the turnout figures account for write-ins. Turnout percentage is the portion of registered voters (632,805 as of January 11, 2012)^[56] who voted.

Quick Facts Turnout, Nominee ...

Florida election

← 2006 2018 →
Turnout	63.5% (voting eligible)[25]
Nominee Bill Nelson Connie Mack IV Party Democratic Republican Popular vote 4,523,451 3,458,267 Percentage 55.2% 42.2%
County results Nelson:      40–50%      50–60%      60–70%      70–80% Mack:      40–50%      50–60%      60–70%
U.S. senator before election Bill Nelson Democratic Elected U.S. senator Bill Nelson[57] Democratic

Close

The primary election was held August 14, 2012. Incumbent Democrat Bill Nelson won re-election to a third term, defeating Republican U.S. Representative Connie Mack IV by 13%, winning 55% to 42%. Nelson defeated Mack by over 1 million votes.

From a long way out Nelson appeared to be vulnerable, with some earlier polls showing Mack leading. However, in the last few weeks with new polls conducted it appeared as though Nelson was headed for a victory. The last poll place him 5 percentage points ahead of Mack. In fact Nelson would win easily by 13 percentage points. Nelson performed well in Southeast Florida (the Miami area), Tampa, Gainesville, typically Democratic areas. Nelson however managed to win in areas that lean Republican. For example, Nelson won in Duval County home of Jacksonville, and Volusia County home of Daytona Beach. Nelson's ability to outperform President Obama led to him winning the Election easily. President Obama would still win Florida, but by just about 74,000 votes, and less than a percentage point. Nelson began his third term in the Senate on January 3, 2013.

Quick Facts Turnout, Nominee ...

Hawaii election

← 2006 2018 →
Turnout	44.2% (voting eligible)[25]
Nominee Mazie Hirono Linda Lingle Party Democratic Republican Popular vote 269,489 160,994 Percentage 62.6% 37.4%
County results Hirono:      50–60%      60–70%      70–80%
U.S. senator before election Daniel Akaka Democratic Elected U.S. senator Mazie Hirono Democratic

Close

Incumbent Democrat Daniel Akaka retired instead of running for re-election to a fourth term. Democratic Congresswoman Mazie Hirono defeated former Hawaii Governor Linda Lingle in a rematch of the 2002 Hawaii gubernatorial election.

Quick Facts Turnout, Nominee ...

2012 United States Senate election in Indiana

← 2006 2018 →
Turnout	58.5%[59]
Nominee Joe Donnelly Richard Mourdock Andrew Horning Party Democratic Republican Libertarian Popular vote 1,281,181 1,133,621 145,282 Percentage 50.0% 44.3% 5.7%
County results Donnelly:      40–50%      50–60%      60–70% Mourdock:      40–50%      50–60%      60–70%
U.S. senator before election Richard Lugar Republican Elected U.S. senator Joe Donnelly Democratic

Close

Incumbent Republican Richard Lugar ran for re-election to a seventh term, but was defeated in the primary by Tea Party-backed Richard Mourdock. Congressman Joe Donnelly, a moderate Democrat from Indiana's 2nd Congressional District, received his party's nomination after running unopposed in the primary contest, and then defeated both Mourdock and Libertarian Andrew Horning in the general election.

Due to Lugar's unpopularity among some Tea Party voters on his positions regarding illegal immigration, voting to confirm then-U.S. Supreme Court nominees Sonia Sotomayor and Elena Kagan, the DREAM Act, the START Treaty, some gun control bills, and congressional earmarks, he was challenged by a Tea Party-backed candidate.^[60][61]

The Indiana Debate Commission's GOP primary debate with Sen. Richard Lugar and State Treasurer Richard Mourdock was set to air at 7 p.m. EDT on Wednesday, April 11.^[62] In a widely published poll taken March 26 to 28, Lugar was still in the lead, but by the time of a second published poll from April 30 to May 1, Mourdock was leading 48% to 38% for Lugar.

Mourdock defeated senator Lugar in the Republican primary on May 8, 2012.^[63][64]

According to Indiana law, Lugar's defeat meant that he would not be permitted to run in the election either as a third party or an independent candidate after he lost the primary.^[65]

Mourdock became embroiled in a controversy after stating that pregnancy from rape is "something that God intended". His remarks were made during a debate on October 23, 2012, while explaining his opposition to abortion even in the case of rape. At the debate Mourdock, when asked what his position on abortion was, responded:

"I know there are some who disagree and I respect their point of view but I believe that life begins at conception. The only exception I have to have an abortion is in that case of the life of the mother. I just struggled with it myself for a long time but I came to realize: "Life is that gift from God that I think even if life begins in that horrible situation of rape, that it is something that God intended to happen."^[67]

Media speculated that this could affect the outcome of the Senate race and Presidential race,^[68] and multiple sources noted the similarities with the rape and pregnancy statement controversies in the 2012 United States elections.^[69][70]

Responding to the criticism, Mourdock issued a statement saying: "God creates life, and that was my point. God does not want rape, and by no means was I suggesting that he does. Rape is a horrible thing, and for anyone to twist my words otherwise is absurd and sick."^[71] He was later quoted at a press conference also saying: "I believe God controls the universe. I don't believe biology works in an uncontrolled fashion."^[72] He however refused to issue an apology, even while prominent Republicans, including Sen. John McCain, called for him to do so.^[73]

On election night Donnelly won by about six percent. He performed well in Marion County, home of Indianapolis. Donnelly also won areas with major college campuses, such as Indiana University in Bloomington, Purdue University in Lafayette. Mourdock performed well, as expected in the Indianapolis suburbs, such as Hamilton County. Mourdock conceded defeat to Donnelly at around 11:30 P.M. EST.

Quick Facts Nominee, Party ...

2012 United States Senate election in Maine

← 2006 2018 →

Nominee Angus King Charlie Summers Party Independent Republican Popular vote 368,724 214,114 Percentage 52.9% 30.7%   Nominee Cynthia Dill Party Democratic Popular vote 91,635 Percentage 13.2%

County results Municipality results King:      30–40%      40–50%      50–60%      60–70%      70–80%      >90% Summers:      30–40%      40–50%      50–60%      60–70%      >90% Dill:      40–50%      60–70%      >90% Tie:      30–40%      40–50%      50–60%

U.S. senator before election Olympia Snowe Republican Elected U.S. senator Angus King Independent

Close

Despite initially being in the race early on and poised to easily win, popular Republican Olympia Snowe suddenly retired instead of running for re-election to a fourth term. Former Independent Governor Angus King won the open seat. Following senator Joe Lieberman's retirement from the Senate in 2013, King became the second Independent incumbent senator, after Vermont's Bernie Sanders.

Incumbent Olympia Snowe won re-election to a third term in 2006 with 74.01% of the vote over Democrat Jean Hay Bright and independent Bill Slavick. Due to the unpopularity of some of Snowe's votes among conservative voters, namely for the American Recovery and Reinvestment Act of 2009 and initial support of the Patient Protection and Affordable Care Act, there was speculation that she would face competition in the 2012 Republican primary from more conservative challengers.^[75] The Tea Party Express had promised to aid in a primary against Snowe.^[76] There had also been speculation that Snowe would switch parties, though she has always denied this.^[77][78][79] By June 2011, Snowe had officially entered her name with signatures to run in the Republican primary, saying, she "would never switch parties".

However, on February 28, 2012, Snowe announced that she would be retiring from the U.S. Senate at the end of her term, citing the "atmosphere of polarization and 'my way or the highway' ideologies has become pervasive in campaigns and in our governing institutions" as the reason for her retirement.^[80] Her announcement opened the door for candidates from all parties and creating a much more contested 2012 election.^[81]

The primary election was held June 12.^[82]

Quick Facts Nominee, Party ...

Maryland election

← 2006 2018 →

Nominee Ben Cardin Dan Bongino Party Democratic Republican Popular vote 1,402,092 674,649 Percentage 55.4% 26.7%   Nominee Rob Sobhani Party Independent Popular vote 420,554 Percentage 16.6%

County results Cardin:      30–40%      40–50%      50–60%      60–70%      70–80%      80–90% Bongino:      30–40%      40–50%      50–60%      60–70%

U.S. senator before election Ben Cardin Democratic Elected U.S. senator Ben Cardin Democratic

Close

Incumbent Democrat Ben Cardin won re-election to a second term, defeating Republican nominee Dan Bongino and independent Rob Sobhani.

In both 2010 and 2009, National Journal magazine rated Cardin as tied for most liberal senator, based on his voting record. As of June 30, Cardin had $1.8 million in his campaign account.^[87]