Most of the political media is devoted, quite understandably, to covering the United States presidential election. However, 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.
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 43%, Brown 38% (Boston Globe 9/27)
- Real Clear Politics Average: Warrant 46.5%, Brown 45.5%
- Nate Silver Probability Analysis: 64.9% 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 two 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. Over the last week Brown has closed the gap in the Real Clear Politics average, but Nate Silver increased Warren’s chances for victory by 4.3 percent.
- Seat Currently Held By: Senator Clair McCaskill (D)
- Challenger: Rep. Todd Akin (R)
- Most Recent Poll: McCaskill 49%, Akin 43% (Rasmussen Reports 9/11)
- Real Clear Politics Average: McCaskill 48%, Akin 42.7%
- Nate Silver Probability Analysis: 67.4% chance of McCaskill win
- Projected Winner: McCaskill
- Analysis: After being considered a swing state for much of the last four decades 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. After being considered a fairly safe pickup for Republicans for much of the year, Akin gave 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. There have been no new polls released since last week. Nate Silver decreased McCaskill’s odds for victory by 4.8 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 42% (PPP 9/26)
- Real Clear Politics Average: Murphy 43.7%, McMahon 41.7%
- Nate Silver Probability Analysis: 75.3% 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. Murphy leads in the most recent poll and widened his lead in the RCP average sine last week.
- Seat Currently Held By: Sen. Dean Heller (R)
- Challenger: Shelly Berkley (D)
- Most Recent Poll: Heller 49%, Berkley 42% (NBC/WSJ 9/25)
- Real Clear Politics Average: Heller 44.8%, Berkley 42.8%
- Nate Silver Probability Analysis: 60.6% chance of Heller win
- Projected Winner: Heller
- Analysis: Nevada is another rare chance for Democrats to pick up a seat currently held by Republicans. Sen. Heller leads in the most recent poll and the Real Clear Politics average. Since last week, Nate Silver increased Heller’s chances for victory by 9.1 percent. For all these reason, the seat is now projected to go for Republicans.
- Seat Currently Held By: Sen. Jim Webb (D)
- Candidates: Tim Kaine (D) versus George Allen (R)
- Most Recent Poll: Kaine 44%, Allen 44% (Suffolk/WWBT 9/26)
- Real Clear Politics Average: Kaine 47.8%, Allen 44.2%
- Nate Silver Probability Analysis: 72.9% 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, and is tied in the most recent poll, but Democrats appear poised to hold on to the seat according to the Real Clear Politics average. Like Nevada, Kaine may also benefit from a down ballot effect since President Obama is also leading in the polls in Virginia.
- Seat Currently Held By: Sen. Herb Kohl (D)
- Candidates: Tammy Baldwin (D) and Tommy Thompson (R)
- Most Recent Poll: Baldwin 52%, Thompson 40% (We Ask America 9/23)
- Real Clear Politics Average: Baldwin 49.2%, Thompson 44.2%
- Nate Silver Probability Analysis: 76.1% 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. However, the polls have trended in favor Democrat Tammy Baldwin over the last month, and she now holds a strong lead in the most recent poll and the Real Clear Politics average. Nate Silver increased Baldwin’s chances of winning by 8.8 percent since last week. President Obama also hold 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: Donnelly 42%, Mourdock 40% (Howey/Depauw 9/23)
- Real Clear Politics Average: Donnelly 40%, Mourdock 38%
- Nate Silver Probability Analysis: 53.5% chance of Donnelly 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 has Donnelly with a small lead, and Donnelly lead in the RCP average of three polls. Still, I project Mourdock for the same reason I projected Democrats to win Virginia and Nevada. 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.
- Seat Currently Held By: Sen. Jon Tester (D)
- Challenger: Denny Rehberg
- Most Recent Poll: Rehberg 48%, Tester 45% (Mason Dixon 9/19)
- Real Clear Politics Average: Rehberg 46.0%, Tester 44.3%
- Nate Silver Probability Analysis: 64.1% 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. Rehberg leads in the most recent poll, and the Real Clear Politics and demographics of Montana both favor Rehberg, and so the seat is projected to go Republican.
- 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 44%, Summers 32%, Dill 14.3%
- Nate Silver Probability Analysis: 86.1% 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 (D)
- Most Recent Poll: Berg 49%, Heitkamp 40% (Rasmussen 7/11)
- Real Clear Politics Average: Berg 48.7%, Heitkamp 43.7%
- Nate Silver Probability Analysis: 81.7% 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. There has been a lack of polling from North Dakota, but the polling that is there favors Republicans and 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).