While the White House is the top prize in this election, both parties are also battling for control of the United States Senate. The Senate holds enormous over public policy. Of course, every law must be passed through the Senate, but Senators also have the authority to confirm judicial nominees, ratify treaties, and impeach federal officers (including the president) under Article 1, Section 8 of the United States Constitution. New polls released over the last 72 hours from Senate races in Massachusetts, Missouri Virginia, and Wisconsin all give Democrats a good chance to keep control of the Senate. Nate Silver’s probability analysis for all ten races, which was updated just today, favors the Democrats in seven out of the ten races listed below.
The Democrats currently control the Senate with a 53-47 majority, but are defending more competitive seats than Republicans. The GOP dreams of a scenario in which Romney takes over the White House and his party controls both the House and Senate. Democrats are trying to hold on to the White House and Senate, with an outside chance of taking over the House where Republicans currently have a majority.
Listed below are the top ten U.S. Senate races that will likely decide who controls the legislative chamber next year. Based on the polls and projections below, as well as polls in other contests not listed here, the Democrats are projected to keep their majority in the Senate by a 52-48 margin. Follow me on Twitter and Facebook or bookmark this page for continual updates leading up to the election.
- Seat Currently Held By: Senator Scott Brown (R)
- Challenger: Elizabeth Warren (D)
- Most Recent Poll: Warren 52%, Brown 47% (Rasmussen 10/25)
- Real Clear Politics Average: Warran 50.7%, Brown 45.0%
- Nate Silver Probability Analysis: 95.2% chance of Warren win
- Projected Winner: Elizabeth Warren
- Analysis: Sen. Scott Brown shocked the political world by winning as a Republican in Massachusetts in 2009, which deprived the Democrats of their filibuster-proof majority in the chamber. Brown has tried to run as a moderate in a state that has demographics that clearly favor Democrats (President Obama won by 26 points here in 2008). Brown was leading in almost every poll over the last few months, but Warren has surged in the past three weeks. Democrats now have a good chance of gaining a seat on Republicans in Massachusetts, which will make it more difficult for Republicans to gain a majority. The Real Clear Politics (RCP) data now has Warren 5.7 points ahead, which is up by 4.0 points since last week. Rasmussen Reports, an organization known for favoring Republican candidates, has Warren with a four point lead. Nate Silver increased Warren’s chances for victory by 6.1 percent.
- Seat Currently Held By: Senator Clair McCaskill (D)
- Challenger: Rep. Todd Akin (R)
- Most Recent Poll: McCaskill 45%, Akin 43% (Post-Dispatch/Mason Dixon 10/25)
- Real Clear Politics Average: McCaskill 47.0%, Akin 42.8%
- Nate Silver Probability Analysis: 88.0% chance of McCaskill win
- Projected Winner: McCaskill
- Analysis: After being considered a swing state for much of the last 40 years Missouri has trended Republican over the last decade. McCaskill won by three points over Rep. Jim Talent in the 2006 election, but the state went to Sen. John McCain in the 2008 presidential election even though Obama won big nationally. Missouri once was considered a fairly safe pickup for Republicans, but Akin stumbled big when he claimed that “legitimate rape” victims cannot get pregnant. McCaskill now leads in the most recent polls, and Democrats are favored to keep the seat. The most recent poll from The St. Louis Post-Dispatch has a tight race, but every poll shows McCaskill winning by a large margin. Nate Silver increased McCaskill’s odds for victory by 1.1 percent.
- Seat Currently Held By: Sen. Joe Lieberman (Independent but caucuses with Democrats)
- Candidates: Rep. Chris Murphy (D) and Linda McMahon (R)
- Most Recent Poll: Murphy 48%, McMahon 47% (Rasmussen 10/21)
- Real Clear Politics Average: Murphy 47.0%, McMahon 44.3%
- Nate Silver Probability Analysis: 85.6% chance of Murphy win
- Projected Winner: Murphy
- Analysis: Sen. Joe Lieberman is retiring which leaves the possibility for a pickup for Republicans. While he caucused with Democrats, Lieberman often voted with Republicans and even campaigned for Sen. John McCain (R-AZ) in the 2008 presidential election. Like Massachusetts, the demographics favor Democrats. The latest poll from Rasmussen gives Murphy only a one point lead, but Murphy still holds a significant lead in the RCP average. Nate Silver increased Murphy’s odds for victory by 7.6 percent.
- Seat Currently Held By: Sen. Dean Heller (R)
- Challenger: Shelly Berkley (D)
- Most Recent Poll: Heller 48%, Berkley 45% (NBC/WSJ/Marist 10/24)
- Real Clear Politics Average: Heller 47.0%, Berkley 43.5%
- Nate Silver Probability Analysis: 71.7% chance of Heller win
- Projected Winner: Heller
- Analysis: Nevada is another rare chance for Democrats to pick up a seat currently held by Republicans. The most recent poll has Helley up by three points, the same margin that RCP has Heller up by in their average of three polls. Since last week, Nate Silver decreased Heller’s chances for victory by 3.2 percent. At this point, the seat is still projected to remain Republican, but Democrats have an opportunity if they make gains in the final weeks.
- Seat Currently Held By: Sen. Jim Webb (D)
- Candidates: Tim Kaine (D) versus George Allen (R)
- Most Recent Poll: Allen 48%, Kaine 46% (Gravis 10/26)
- Real Clear Politics Average: Kaine 48.7%, Allen 46.7%
- Nate Silver Probability Analysis: 92.4% chance of Kaine win
- Projected Winner: Kaine
- Analysis: In 2006 Allen was defeated by just one percentage point against Jim Webb. Sen. Webb is not running again, leaving former Gov. Tim Kaine (D) to fight for the seat. Allen has a small lead in the most recent poll, but an average fo all the polls still gives Kaine a substantial lead. Nate Silver increased Kaine’s chances for victory by 10.4 percent over the last week. At this point, the seat appears to be a solid hold for Democrats.
- Seat Currently Held By: Sen. Herb Kohl (D)
- Candidates: Tammy Baldwin (D) and Tommy Thompson (R)
- Most Recent Poll: Thompson 48%, Baldwin 47% (Rasmussen 10/25)
- Real Clear Politics Average: Baldwin 47.0%, Thompson 46.0%
- Nate Silver Probability Analysis: 82.9% chance of Baldwin win
- Projected Winner: Baldwin
- Analysis: Five-term U.S. Senator Herb Kohl decided not to run for re-election which gave Republicans another prime opportunity to pick up a seat from Democrats. The most recent polls show the race tightening, and Rasmussen Reports now haw Thompson in the lead. Nate Silver decreased Baldwin’s chances of winning by 2.2 percent since last week. Still, the odds are currently in Baldwin’s favor. President Obama also holds a large lead in the Badger State according to the most recent polls, so Baldwin could benefit if the Romney campaign gives up on Wisconsin.
- Seat Currently Held By: Senator Richard Lugar (R)
- Candidates: Richard Mourdock (R) and Joe Donnelly (D)
- Most Recent Poll: Mourdock 47%, Donnelly 42% (Rasmussen 10/11)
- Real Clear Politics Average: None available.
- Nate Silver Probability Analysis: 63.9% chance of Mourdock win
- Projected Winner: Mourdock
- Analysis: Long-time Senator Richard Lugar (R) was defeated in the Republican primary. Lugar was known as a moderate Republican, a group that is increasingly an endangered in today’s politics. The most recent poll from Rasmussen now has Mourdock with a five point lead. There is no RCP average available given the scarcity of polls from this state. Mitt Romney currently leads big over Obama in Indiana, and Mourdock may therefore benefit from increased turnout from his voters in an otherwise close election. Mourdock did stumble in the most recent debate when discussing rape and abortion, but there is no polling available to see if his comments did any damage.
- Seat Currently Held By: Sen. Jon Tester (D)
- Challenger: Denny Rehberg
- Most Recent Poll: Tester 48%, Rehberg 48% (Rasmussen 10/14)
- Real Clear Politics Average: Rehberg 46.3%, Tester 46.0%
- Nate Silver Probability Analysis: 63.5% chance of Rehberg win
- Projected Winner: Rehberg
- Analysis: Sen. Tester won by just one percent in 2006, and now faces a tough race in an election year that favors Republicans more than it did when he ran six years ago. Tester has gained momentum over the last week and is now tied in Rasmussen’s latest poll, but the Real Clear Politics and demographics of Montana both favor Rehberg, and so the seat is projected to go Republican. Nate Silver has increased Rehberg’s odds for victory by 6.7 percent.
- Seat Currently Held By: Sen. Olympia Snowe (R)
- Candidates: Angus King (I), Charlie Summers (R), and Cynthia Dill (D)
- Most Recent Poll: King 45%, Summers 33%, Dill 14% (Rasmussen 9/25)
- Real Clear Politics Average: King 46.0%, Summers 30.7%, Dill 13.3%
- Nate Silver Probability Analysis: 91.4% chance of King win
- Projected Winner: King
- Analysis: Democrats had an opportunity to pick up a seat after long-time Senator Olympia Snowe (R) decided not to run for re-election. However, the race changed when former governor and independent Angus King decided to run as an independent. King is now the overwhelming favorite, but the big question is which party he will caucus with if he wins re-election. Regardless, the Republicans have everything to lose in this race since the seat was formerly held by one of their own. Even if King caucuses with Republicans, he may prove an even less reliable vote than Snowe, opening up the possibility for more compromise with Democrats in the Senate.
- Seat Currently Held By: Sen. Kent Conrad (D)
- Candidates: Heidi Heitkamp (D) and Rick Berg (R)
- Most Recent Poll: Berg 50%, Heitkamp 40% (Forum/Essman 10/15)
- Real Clear Politics Average: Berg 49.0%, Heitkamp 44.0%
- Nate Silver Probability Analysis: 86.6% chance of Berg win
- Projected Winner: Berg
- Analysis: Powerful Sen. Kent Conrad (D) decided to retire rather than face a tough re-election campaign, which opened the opportunity for Republicans to gain a seat. The most recent poll gives Berg a large ten point lead and Berg has a significant edge in the RCP average. Nate Silver gives Republicans good odds to win given the demographics of North Dakota and all the other factors Silver accounts for in this election (which are many).