The 2006 United States Senate elections were held on November 7, 2006, with all 33 Class 1 Senate seats being contested. The term of office for those elected in 2006 ran from January 3, 2007, to January 3, 2013. Before the election cycle, the Republican Party controlled 55 of the 100 Senate seats.
The Senate elections were part of the Democratic sweep during the 2006 elections, in which Democrats made numerous gains and no congressional or gubernatorial seat held by a Democrat was won by a Republican. However, Democratic incumbent Joe Lieberman in Connecticut was defeated in the primary and was later reelected as a third-party candidate; he continued to caucus with the Democrats. Because of this, this is the first time since 1970 in which a member of a third party, who is not an independent, was elected to the Senate. Independent Jim Jeffords in Vermont retired but was succeeded by another Independent, Bernie Sanders, retaining their presence in the Senate. Jeffords and Sanders both caucused with Democrats. Democrats picked 6 seats up by defeating Republican incumbents in Missouri, Montana, Pennsylvania, Ohio, Rhode Island, and Virginia, while holding open seats in Maryland and Minnesota. Republicans held their sole open seat in Tennessee. As of 2022, this is the most recent midterm in which none of the open seats flipped parties.
Following the elections, no party held a majority of seats for the first time since January 1955. The Democrats were able to control the chamber because the two Independents caucused with the Democrats. They needed at least 51 seats to control the Senate because Vice President Dick Cheney would have broken any 50–50 tie in favor of the Republicans. This was the only time between 1990 and 2022 that Democrats gained Senate seats in a midterm.
, this was the last time a Democrat won a Senate election in Nebraska, the last time a Democrat did not win a seat in Connecticut, and the last time that the tipping point state was decided by under 1%, with Jim Webb of Virginia winning by a margin of under 0.4%.
Results summary + ↓ 49 2 49 Democratic Independent Republican Summary of the November 7, 2006, United States Senate election results Parties Total Republican Democratic Independent Libertarian Green Independence Constitution Others Before these elections 55 44 1 — — — — — 100 Not Up Total 40 27 — — — — — — 67 21 12 0 — — — — — 33 19 15 0 — — — — — 34 Up Class 1 15 17 1 — — — — — 33 Incumbentretired 1 2 1 — — — — — 4 — — — — — — — — 0 Incumbentran Total before 14 15 — — — — — — 29 8 14 — — — — — — 22 6 Republicans replacedby 6 Democrats — — — — — — 6 — — — — — — — — 0 — 1 Democrat re-electedas an Independent — — — — — 1 Result after 8 20 1 — — — — — 29 Net gain/loss 6 5 1 — — — — — 6 Total elected 9 22 2 — — — — — 33 Result 49 49 2 — — — — — 100 Popularvote Votes (turnout: 29.7 %) 25,437,934 32,344,708 378,142 612,732 295,935 231,899 26,934 1,115,432 60,839,144 Share 41.81% 53.16% 0.62% 1.01% 0.49% 0.38% 0.04% 1.83% 100% Sources: Dave Leip's Atlas of U.S. Elections United States Elections Project at George Mason University
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 I R R 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
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 D D D I Majority (with Independents) ↑ I 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 I Independent R Republican
Final pre-election predictions
State Incumbent Last election Crystal Ball, Rothenberg, Cook, Result Arizona Jon Kyl 79.3% R Kyl53.3% R California Dianne Feinstein 55.8% D Feinstein59.4% D Connecticut Joe Lieberman 63.2% D Lieberman49.7% I Delaware Tom Carper 55.5% D Carper67.1% D Florida Bill Nelson 51% D Nelson60.3% D Hawaii Daniel Akaka 72.7% D Akaka61.4% D Indiana Richard Lugar 66.5% R Lugar87.3% R Maine Olympia Snowe 68.9% R Snowe74.4% R Maryland Paul Sarbanes 63.2% D Cardin54.2% D Massachusetts Ted Kennedy 72.9% D Kennedy69.5% D Michigan Debbie Stabenow 49.4% D Stabenow56.9% D Minnesota Mark Dayton 48.8% D Klobuchar58.1% D Mississippi Trent Lott 65.9% R Lott63.6% R Missouri Jim Talent 49.8% R McCaskill49.6% D Montana Conrad Burns 50.6% R Tester49.2% D Nebraska Ben Nelson 51% D Nelson63.9% D Nevada John Ensign 55.1% D Ensign55.4% R New Jersey Bob Menendez Appointed Menendez53.4% D New Mexico Jeff Bingaman 61.7% D Bingaman70.6% D New York Hillary Clinton 55% D Clinton67.0% D North Dakota Kent Conrad 61.4% D Conrad68.8% D Ohio Mike DeWine 59.9% R Brown56.2% D Pennsylvania Rick Santorum 52.4% R Casey58.7% D Rhode Island Lincoln Chafee 56.8% R Whitehouse53.5% D Tennessee Bill Frist 65.1% R Corker50.7% R Texas Kay Bailey Hutchison 65% R Hutchison61.7% R Utah Orrin Hatch 65.6% R Hatch62.6% R Vermont Jim Jeffords 65.6% R Sanders65.4% I Virginia George Allen 52.3% R Webb49.6% D Washington Maria Cantwell 48.7% D Cantwell56.9% D West Virginia Robert Byrd 77.7% D Byrd64.4% D Wisconsin Herb Kohl 61.5% D Kohl67.3% D Wyoming Craig L. Thomas 73.7% R Thomas70.0% R
Race summary Special elections during the 109th Congress There were no special elections during the 109th Congress.
Elections leading to the next Congress In these general elections, the winners were elected for the term beginning January 3, 2007; ordered by state.
All of the elections involved the Class 1 seats.
State Incumbent Result Candidates Senator Party Electoral history Arizona Republican 19942000 Incumbent re-elected. California Democratic 1992 19942000 Incumbent re-elected. Connecticut Democratic 198819942000 Incumbent lost renomination, but re-elected as an independent.Independent Democratic gain. Delaware Democratic 2000 Incumbent re-elected. Florida Democratic 2000 Incumbent re-elected. Hawaii Democratic 1990 1990 19942000 Incumbent re-elected. Indiana Republican 19761982198819942000 Incumbent re-elected. Maine Republican 19942000 Incumbent re-elected. Maryland Democratic 19761982198819942000 Incumbent retired.Democratic hold. Massachusetts Democratic 1962 1964197019761982198819942000 Incumbent re-elected. Michigan Democratic 2000 Incumbent re-elected. Minnesota DFL 2000 Incumbent retired.Democratic (DFL) hold. Mississippi Republican 198819942000 Incumbent re-elected. Missouri Republican 2002 Incumbent lost re-election.Democratic gain. Montana Republican 198819942000 Incumbent lost re-election.Democratic gain. Nebraska Democratic 2000 Incumbent re-elected. Nevada Republican 2000 Incumbent re-elected. New Jersey Democratic 2006 Interim appointee elected. New Mexico Democratic 1982198819942000 Incumbent re-elected. New York Democratic 2000 Incumbent re-elected. North Dakota Democratic-NPL 19861992 1992 19942000 Incumbent re-elected. Ohio Republican 19942000 Incumbent lost re-election.Democratic gain. Pennsylvania Republican 19942000 Incumbent lost re-election.Democratic gain. Rhode Island Republican 1999 2000 Incumbent lost re-election.Democratic gain. Tennessee Republican 19942000 Incumbent retired.Republican hold. Texas Republican 1993 19942000 Incumbent re-elected. Utah Republican 19761982198819942000 Incumbent re-elected. Vermont Independent 198819942000 Incumbent retired.Independent hold. Virginia Republican 2000 Incumbent lost re-election.Democratic gain. Washington Democratic 2000 Incumbent re-elected. West Virginia Democratic 19581964197019761982198819942000 Incumbent re-elected. Wisconsin Democratic 198819942000 Incumbent re-elected. Wyoming Republican 19942000 Incumbent re-elected.
Closest races
In eight races the margin of victory was under 10%.
District Winner Margin Virginia Democratic (flip) 0.4% Montana Democratic (flip) 0.9% Missouri Democratic (flip) 2.3% Tennessee Republican 2.7% Rhode Island Democratic (flip) 7.0% New Jersey Democratic 9.0% Arizona Republican 9.8% Connecticut Independent (flip) 9.9%
Gains and losses
Retirements Two Democrats, one Republican, and one Independent retired rather than seek re-election. StateSenator Age at end of term AssumedofficeReplaced by Maryland 73 1977 Minnesota 59 2001 Tennessee 54 1995 Vermont 72 1989
Defeats Six Republicans and one Democrat sought re-election but lost in the primary or general election. StateSenatorAge atend of termAssumedofficeReplaced by Connecticut colspan="2" align="center" Missouri 50 2002 Montana 71 1989 Ohio 59 1995 Pennsylvania 48 1995 Rhode Island 53 1999 Virginia 54 2001
Post-election changes One Republican died on June 4, 2007, and was replaced by a Republican appointee on June 22, 2007. One other Republican resigned on December 18, 2007, and was replaced by a Republican appointee on December 31, 2007.
StateSenatorReplaced by Mississippi(Class 1) Wyoming(Class 1)
Arizona
Incumbent Republican Jon Kyl won re-election to a third term over Democrat Jim Pederson, real estate developer and former chairman of the Arizona Democratic Party.
The incumbent, Republican Jon Kyl, was elected to the Senate in 1994 and was re-elected to a second term in 2000; having previously spent eight years in the U.S. House of Representatives. Kyl's Democratic opponent for the general election was wealthy real-estate developer Jim Pederson, who served as the Arizona Democratic Party Chairman from 2001 to 2005. During his tenure, Pederson spent millions of dollars of his own money to help Democrats modernize and to elect Janet Napolitano as Governor of Arizona. The deadline for signing petition signatures to appear on the September 12, 2006, primary ballot was June 14, 2006.
Not long after the 2004 election, Pederson's name began being mentioned as a potential Senate candidate for the 2006 race. On July 28, 2005, Pederson formally stepped down as Chairman of the Arizona Democratic Party, further fueling those speculations. In early September 2005, an e-mail was sent from the Arizona Democratic Party's website, inviting people to an announcement by Pederson on September 7. In an anticlimactic move, an e-mail was sent out shortly after the first saying that the announcement would be postponed due to Hurricane Katrina. It was requested that any money that would be donated to Pederson's campaign at the announcement be directed to relief efforts instead. Similarly, a meeting in Arizona of the Democratic National Committee (DNC) was scheduled for around the same time. It was also postponed and the same request was made involving donations. On September 7, 2005, Pederson filed to run for the U.S. Senate. On September 14, 2005, Pederson formally announced his intention to run, in his hometown of Casa Grande, Arizona.
Although Kyl started the campaign with a sizable lead in most polls, the gap quickly narrowed, especially after Pederson released his array of ads.
Pederson lost the election by 9.84% or 150,257 votes, despite Democratic Incumbent Governor Janet Napolitano easily being re-elected and winning every county statewide. While Pederson lost it was still notable, as it was the worst performance of Senator Kyl's career. Kyl did well as Republicans usually do in Maricopa County home of Phoenix. Pederson did well in Pima County home of Tucson which tends to support Democrats. Kyl was called the winner by CNN at around 8 P.M. local time, 11 P.M. EST. Pederson called Senator Kyl and conceded defeat at 9:02 p.m. local time, 12:02 A.M. EST.
California
Incumbent Democrat Dianne Feinstein won re-election to her third full term.
The Republican candidate was Dick Mountjoy, who had never held a statewide elected position, but had been a state senator for several years. Also running was Libertarian Michael Metti, Don Grundmann of the American Independent Party, Todd Chretien of the Green Party and Marsha Feinland of the Peace and Freedom Party.