# 2012 United States Senate election in Wisconsin

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vte :
The 2012 United States Senate election in Wisconsin took place on November 6, 2012, alongside a U.S. presidential election as well as other elections to the United States Senate and House of Representatives and various state and local elections. Incumbent Democratic Senator Herb Kohl retired instead of running for re-election to a fifth term. This was the first open Senate seat in Wisconsin since 1988, when Kohl won his first term.
Primary elections were held on August 14, 2012. Congresswoman Tammy Baldwin of Wisconsin's 2nd congressional district ran unopposed in the Democratic primary. The Republican nominee was former Wisconsin Governor and U.S. Secretary of Health and Human Services Tommy Thompson, who won with a plurality in a four-way primary race. In the general election, Baldwin defeated Thompson and won the open seat. She became the first woman elected to represent Wisconsin in the Senate and the first openly gay U.S. senator in history. This is also the only time Thompson lost a statewide race.

## Background

Incumbent Democratic senator Herb Kohl was re-elected to a fourth term in 2006, beating Republican attorney Robert Lorge by 67% to 30%. Kohl's lack of fundraising suggested his potential retirement. There was speculation that Kohl might decide to retire to allow Russ Feingold, who lost his re-election bid in 2010, to run again, although Mike Tate, chairman of the Wisconsin Democratic Party, dismissed speculation about Kohl's potential retirement. Ultimately, Kohl announced in May 2011 that he would not run for re-election in 2012.

## Democratic primary

Despite speculation that Kohl would retire to make way for his former Senate colleague Russ Feingold, who had been unseated in 2010, Feingold chose not to enter the race. Other potential candidates also declined to run, leaving Baldwin unopposed in the Democratic primary.

### Candidates
#### Declared

* Tammy Baldwin, U.S. representative

#### Declined

* Tom Barrett, mayor of Milwaukee
* Kathleen Falk, former Dane County executive (1997–2011)
* Russ Feingold, former U.S. senator
* Steve Kagen, former U.S. representative for Wisconsin's 8th congressional district (2006–2011)
* Ron Kind, U.S. representative for Wisconsin's 3rd congressional district
* Herb Kohl, incumbent U.S. senator
* Gwen Moore, U.S. representative for Wisconsin's 4th congressional district
* Tim Sullivan, businessman

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin | Jon Erpenbach | Russ Feingold | Kathleen Falk | Steve Kagen | Ron Kind | Barbara Lawton | Gwen Moore | Other/ Undecided |
| Public Policy Polling | May 19–22, 2011 | 783 | ±3.5% | 12% | 5% | 70% | 1% | 3% | 4% | 1% | 2% | 3% |
| Public Policy Polling | May 19–22, 2011 | 783 | ±3.5% | 30% | 13% | — | 4% | 17% | 16% | 3% | 6% | 12% |
| Magellan Strategies | July 12–13, 2011 | 627 | ±3.9% | 46% | — | — | — | 21% | — | — | — | 33% |
| Magellan Strategies | July 12–13, 2011 | 627 | ±3.9% | 41% | — | — | — | — | 19% | — | — | 40% |
| Public Policy Polling | August 12–14, 2011 | 387 | ±5% | 48% | — | — | — | 19% | — | — | — | 33% |
| Public Policy Polling | August 12–14, 2011 | 387 | ±5% | 37% | — | — | — | 15% | 21% | — | — | 27% |

### Results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Tammy Baldwin | 185,265 | 99.77 |
| | Democratic | Write ins | 424 | 0.23 |
| Total votes | Total votes | Total votes | 185,689 | 100 |

## Republican primary

Congressman and House Budget Committee Chairman Paul Ryan stated he would not run if Kohl sought reelection, but would contemplate a run if Kohl retired. Ryan later stated that he was "95 percent sure" that he would not run. He was later chosen as the Republican nominee for vice president by presidential nominee Mitt Romney.
Six candidates declared for the seat, although two later withdrew. The contest turned out to be a four-way fight. Although a large majority of Republican primary voters consistently expressed a preference for a nominee "more conservative" than Tommy Thompson, Eric Hovde and Mark Neumann split the conservative vote, allowing Thompson to narrowly prevail with a plurality of the vote.

### Candidates
#### Declared

* Jeff Fitzgerald, Speaker of the Wisconsin State Assembly
* Eric Hovde, businessman
* Mark Neumann, former U.S. representative, nominee for the U.S. Senate in 1998, and candidate for governor in 2010
* Tommy Thompson, former governor of Wisconsin and former secretary of Health and Human Services

#### Withdrew

* Frank Lasee, state senator (endorsed Eric Hovde)
* Kip Smith, physical therapist

#### Declined

* Mark Andrew Green, former U.S. representative and former United States ambassador to Tanzania
* Theodore Kanavas, former state senator
* Paul Ryan, U.S. representative
* Tim Sullivan, businessman
* J. B. Van Hollen, Wisconsin attorney general

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Jeff Fitzgerald | Eric Hovde | Mark Neumann | Tommy Thompson | Undecided |
| Public Policy Polling | August 8–9, 2012 | 557 | ± 4.2% | 15% | 27% | 24% | 25% | 9% |
| Marquette University | August 2–5, 2012 | 519 | ± 4.4% | 13% | 20% | 18% | 28% | 7% |
| We Ask America | July 31, 2012 | 1,237 | ± 2.8% | 12% | 23% | 17% | 23% | 25% |
| Public Policy Polling | July 30–31, 2012 | 400 | ± 4.9% | 13% | 28% | 25% | 25% | 9% |
| Public Policy Polling | July 30–31, 2012 | 400 | ± 4.9% | — | 33% | 27% | 30% | 10% |
| Marquette University | July 5–8, 2012 | 432 | ± 4.8% | 6% | 23% | 10% | 35% | 25% |
| Public Policy Polling | July 5–8, 2012 | 564 | ± 4.1% | 9% | 31% | 15% | 29% | 16% |
| OnMessage Inc.$^+$ | June 26–27, 2012 | 600 | ± 4.0% | 7% | 29% | 16% | 34% | 14% |
| Marquette University | June 13–16, 2012 | 344 | ± 5.4% | 10% | 14% | 16% | 34% | 25% |
| Public Policy Polling | March 31–April 1, 2012 | 609 | ± 4.0% | 18% | — | 25% | 38% | 19% |
| Public Policy Polling | February 23–26, 2012 | 556 | ± 4.2% | 22% | — | 22% | 39% | 17% |
| Public Policy Polling | February 23–26, 2012 | 556 | ± 4.2% | 32% | — | 42% | — | 26% |
| Public Policy Polling | February 23–26, 2012 | 556 | ± 4.2% | 37% | — | — | 46% | 17% |
| Public Policy Polling | February 23–26, 2012 | 556 | ± 4.2% | — | — | 36% | 46% | 18% |
| Public Policy Polling | October 20–23, 2011 | 650 | ± 3.8% | 21% | — | 29% | 35% | 11% |
| Public Policy Polling | October 20–23, 2011 | 650 | ± 3.8% | — | — | 39% | 43% | 17% |
| Public Policy Polling | October 20–23, 2011 | 650 | ± 3.8% | 28% | — | 44% | — | 28% |
| Public Policy Polling | October 20–23, 2011 | 650 | ± 3.8% | 35% | — | — | 47% | 17% |
| Public Policy Polling | August 12–14, 2011 | 362 | ± 5.2% | — | — | 39% | 47% | 13% |
| Magellan Strategies | July 12–13, 2011 | 638 | ± 3.9% | 15% | — | 26% | 41% | 18% |
| Magellan Strategies | July 12–13, 2011 | 638 | ± 3.9% | — | — | 36% | 44% | 20% |
* $^+$ Commissioned by Eric Hovde
| Poll source | Date(s) administered | Sample size | Margin of error | Tommy Thompson | Someone more conservative | Undecided |
| Public Policy Polling | July 30–31, 2012 | 400 | ± 4.9% | 29% | 58% | 13% |
| Public Policy Polling | July 5–8, 2012 | 564 | ± 4.1% | 34% | 50% | 17% |
| Public Policy Polling | February 23–26, 2012 | 556 | ± 4.2% | 37% | 47% | 17% |
| Public Policy Polling | October 20–23, 2011 | 650 | ± 3.8% | 35% | 51% | 14% |

### Endorsements

* Scott Suder, Wisconsin Assembly Majority Leader (Abbotsford)
* Robin Vos, Wisconsin Assembly Finance Chair (Rochester)
* Joan Ballweg, Wisconsin Assembly Caucus Chair (Markesan)
* Mary Williams, Wisconsin Assembly Caucus Secretary (Medford)
* Samantha Kerkman, Wisconsin Assembly Caucus Sergeant at Arms (Randall)
* Bill Kramer, Wisconsin Assembly Speaker Pro-Temp (Waukesha)
* Dan Knodl, Wisconsin Assembly Assistant Assembly Majority Leader (Germantown)
* Joel Kleefisch, Wisconsin State Representative (Oconomowoc)
* Don Pridemore, Wisconsin State Representative (Hartford)
* Paul Farrow, Wisconsin State Representative (Pewaukee)
* Dale Kooyenga, Wisconsin State Representative (Brookfield)
* Mike Kuglitsch, Wisconsin State Representative (New Berlin)
* Jim Ott, Wisconsin State Representative (Brown Deer)
* Frank Lasee, Wisconsin State Senator (De Pere)
* Leah Vukmir, Wisconsin State Senator (Wauwatosa)
* FreedomWorks
* Club for Growth
* Family Research Council
* Rand Paul, U.S. Senator (KY)
* Tom Coburn, U.S. Senator (OK)
* Jim DeMint, U.S. Senator (SC)
* Mike Lee, U.S. Senator (UT)
* Jack Voight, former Wisconsin State Treasurer
* Kurt W. Schuller, Wisconsin State Treasurer
* GING PAC, a PAC of Social Conservatives
* Pat Toomey, U.S. Senator (PA)
* Wisconsin Right to Life
* Mark Levin, Nationally Syndicated Talk Show Host
Politicians
* Herman Cain, business executive, radio host, syndicated columnist, former candidate for the 2012 U.S. Republican Party presidential nomination.
* Newt Gingrich, former speaker of the House of Representatives, and 2012 presidential candidate
* Governor Mitch Daniels of Indiana
* Rudy Giuliani, former mayor of New York City and 2008 Presidential Candidate
* Lamar Alexander, U.S. senator from Tennessee
* John Hoeven, U.S. senator from North Dakota
* Mike Johanns, U.S. senator from Nebraska
* Jim Risch, U.S. senator from Idaho
* Mark Green, former U.S. representative and former United States Ambassador to Tanzania
* J.B. Van Hollen, Wisconsin attorney general
* Cathy Zeuske, former Wisconsin state treasurer
* Mike Huckabee, former governor of Arkansas, 2008 presidential candidate and Fox News talk show host
* Scott Klug, former U.S. representative (WI)
* Margaret Farrow, former lieutenant governor of Wisconsin
* Mike Leavitt, former governor of Utah, former Administrator of the EPA, and former Secretary of Health and Human Services
* John Engler, former governor of Michigan
* Dirk Kempthorne, former governor of Idaho and former Secretary of the Interior
* Frank Keating, former governor of Oklahoma
* Tom Ridge, former governor of Pennsylvania and former Secretary of Homeland Security
* Bill Weld, former governor of Massachusetts
* Bill Graves, former governor of Kansas
* Jeb Bush, former Florida governor
Celebrities and political commentators
* Ted Nugent, musician and conservative activist
* Michael Reagan, author, radio host, and son of President Ronald Reagan
* Dick Morris, political strategist, author, Fox News analyst, former adviser to President Bill Clinton
* Joe Wurzelbacher, a.k.a. Joe the Plumber
Cabinet officials
* Donald Rumsfeld, former Secretary of Defense from 1975 to 1977 and 2001 to 2006, former White House chief of staff, and former ambassador
* Donald L. Nelson, former deputy assistant Secretary of Defense
* Ray Boland, colonel and former Veterans Affairs Secretary
State legislators
* John Gard, former Wisconsin Assembly Speaker
* State Senator Rob Cowles
* State Senator Mike Ellis
* Rep. Evan Wynn (Whitewater)
* Rep. Joseph Knilans (Janesville)
* State Senator Sheila Harsdorf
* State Senator Luther Olsen
* State Senator Dale Schultz
* State Senator Jerry Petrowski
* Van Wanggaard, former state senator
Political organization officials
* David Keene, president of the National Rifle Association of America and former chairman of the American Conservative Union
* Former Republican Party of Wisconsin Chairman Rick Graber
* Wisconsin Club for Growth founders Terry and Mary Kohler
* Former Wisconsin Federation of Republican Women President Sue Lynch
* Former Wisconsin Federation of Republican Women President Ginny Marschman
* Republican National Convention co-chairman Mary Buestrin
Law enforcement officials
* Waukesha County Sheriff Daniel Trawicki
* Waukesha County District Attorney Brad Schimel
Organizations
* Wisconsin Right to Life
* Dairy Business Association
* Wisconsin Corn Growers Association
* Wisconsin Farm Bureau Federation
* Milwaukee Police Association
* Milwaukee Police Supervisors Organization
* Milwaukee Professional Firefighters Association
* Wisconsin Grocers Association
* Wisconsin Restaurant Association
* Chiropractic Society of Wisconsin
* Wisconsin Health Care Association
* Wisconsin Mortgage Bankers Association
* GOProud

### Results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Tommy Thompson | 197,928 | 34.0 |
| | Republican | Eric Hovde | 179,557 | 30.8 |
| | Republican | Mark Neumann | 132,786 | 22.8 |
| | Republican | Jeff Fitzgerald | 71,871 | 12.3 |
| | Republican | Write ins | 244 | 0.04 |
| Total votes | Total votes | Total votes | 582,630 | 100 |

## General election
### Candidates

* Tammy Baldwin (Democratic), U.S. Representative
* Tommy Thompson (Republican), former governor and former Secretary of Health and Human Services
* Joseph Kexel (Libertarian), IT consultant
* Nimrod Allen III (independent), consultant and former Marine

### Debates

Baldwin and Thompson agreed to three debates: September 28, October 18 and 26, all broadcast statewide, and nationwide through C-SPAN.
The first debate originated from the studios of Milwaukee Public Television and was coordinated by the Wisconsin Broadcasters Association. It aired on MPTV, Wisconsin Public Television, Wisconsin Public Radio and several commercial stations throughout the state.
The second debate originated from the Theater for Civic Engagement on the campus of the University of Wisconsin–Marathon County in Wausau and was coordinated by WPT/WPR, the Milwaukee Journal Sentinel and Milwaukee's WTMJ-TV. Again it was carried on MPTV, WPT/WPR, and several commercial stations, including WTMJ-TV.
The third debate originated from Eckstein Hall on the campus of Marquette University Law School and was coordinated by WISN-TV in Milwaukee. It aired on that station and across the state's other ABC affiliated stations.
External links
* Complete video of debate, September 28, 2012 - C-SPAN
* Complete video of debate, October 18, 2012 - C-SPAN
* Complete video of debate, October 26, 2012 - C-SPAN

### Fundraising

| Candidate (party) | Receipts | Disbursements | Cash on hand | Debt |
| Tammy Baldwin (D) | $14,643,869 | $15,204,940 | $143,852 | $0 |
| Tommy Thompson (R) | $9,585,823 | $9,582,888 | $2,934 | $0 |
| Source: Federal Election Commission |||||

#### Top contributors

| Tammy Baldwin | Contribution | Tommy Thompson | Contribution |
| EMILY's List | $431,843 | Michael Best & Friedrich LLP | $36,825 |
| MoveOn.org | $171,467 | ABC Supply | $28,500 |
| University of Wisconsin | $117,600 | Akin Gump Strauss Hauer & Feld | $28,250 |
| J Street PAC | $113,758 | Direct Supply | $27,500 |
| League of Conservation Voters | $95,308 | Wisconsin Energy Corporation | $25,750 |
| Democracy Engine | $81,330 | American Foods Group | $25,000 |
| Council for a Livable World | $54,130 | Gilead Sciences | $23,000 |
| Voices for Progress | $25,749 | Centene Corporation | $20,750 |
| Marshfield Clinic | $21,800 | BGR Group | $20,500 |
| Microsoft Corporation | $18,564 | C. R. Bard, Inc. | $20,000 |
| Source: OpenSecrets ||||

#### Top industries

| Tammy Baldwin | Contribution | Tommy Thompson | Contribution |
| Women's Issues | $915,482 | Retired | $858,276 |
| Retired | $791,756 | Leadership PACs | $244,804 |
| Lawyers/Law Firms | $597,674 | Financial Institutions | $243,636 |
| Democratic/Liberal | $555,792 | Lawyers/Law Firms | $228,379 |
| Leadership PACs | $309,430 | Real Estate | $227,687 |
| Universities | $298,298 | Pharmaceuticals/Health Products | $204,302 |
| Human Rights Organizations | $215,539 | Insurance Industry | $202,654 |
| Health Professionals | $202,654 | Manufacturing & Distributing | $169,104 |
| Pro-Israel | $172,380 | Health Professionals | $150,149 |
| Business Services | $163,238 | Lobbyists | $138,700 |
| Source: OpenSecrets ||||

### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Tossup | November 1, 2012 |
| Sabato's Crystal Ball | Lean D | November 5, 2012 |
| Rothenberg Political Report | Tossup | November 2, 2012 |
| Real Clear Politics | Tossup | November 5, 2012 |

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin (D) | Tommy Thompson (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 44% | 45% | — | 11% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 42% | 50% | — | 8% |
| Public Policy Polling | October 20–23, 2011 | 1,170 | ±2.9% | 44% | 46% | — | 10% |
| Rasmussen Reports | October 26, 2011 | 500 | ±4.5% | 42% | 49% | 4% | 6% |
| Marquette University | February 16–19, 2012 | 716 | ±3.7% | 42% | 48% | 1% | 9% |
| Public Policy Polling | February 23–26, 2012 | 900 | ±3.3% | 46% | 45% | — | 9% |
| Rasmussen Reports | February 27, 2012 | 500 | ±4.5% | 36% | 50% | 4% | 10% |
| Rasmussen Reports | March 27, 2012 | 500 | ±4.5% | 44% | 48% | 4% | 4% |
| Public Policy Polling | April 13–15, 2012 | 1,136 | ±2.9% | 45% | 47% | — | 8% |
| Rasmussen Reports | May 9, 2012 | 500 | ±4.5% | 38% | 50% | 5% | 7% |
| Public Policy Polling | May 11–13, 2012 | 851 | ±3.4% | 42% | 47% | — | 11% |
| Rasmussen Reports | June 12, 2012 | 500 | ±4.5% | 36% | 52% | 6% | 6% |
| Marquette University | June 13–16, 2012 | 707 | ±3.8% | 41% | 49% | — | 10% |
| Public Policy Polling | July 5–8, 2012 | 1,057 | ±3.0% | 45% | 45% | — | 11% |
| Marquette University | July 5–8, 2012 | 810 | ±3.5% | 41% | 45% | — | 14% |
| Rasmussen Reports | July 25, 2012 | 500 | ±4.5% | 48% | 41% | 5% | 6% |
| Marquette University | August 2–5, 2012 | 1,400 | ±2.6% | 43% | 48% | — | 5% |
| Quinnipiac | July 31 – August 6, 2012 | 1,428 | ±2.6% | 47% | 47% | 1% | 5% |
| Rasmussen Reports | August 15, 2012 | 500 | ±4.5% | 43% | 54% | 1% | 3% |
| Public Policy Polling | August 16–19, 2012 | 1,308 | ±2.7% | 44% | 49% | — | 7% |
| Marquette University | August 16–19, 2012 | 576 | ±4.2% | 41% | 50% | — | 9% |
| CBS/NYT/Quinnipiac | August 15–21, 2012 | 1,190 | ±3.0% | 44% | 50% | 1% | 4% |
| YouGov | September 4–11, 2012 | 772 | ±n/a | 42% | 48% | — | 10% |
| Public Policy Polling | September 12–13, 2012 | 959 | ±n/a | 48% | 45% | — | 6% |
| Marquette University | September 13–16, 2012 | 705 | ±3.8% | 50% | 41% | — | 5% |
| CBS/NYT/Quinnipiac | September 11–17, 2012 | 1,485 | ±2.5% | 47% | 47% | — | 6% |
| NBC/WSJ/Marist Poll | September 16–18, 2012 | 968 | ±3.2% | 48% | 46% | — | 5% |
| Public Policy Polling | September 18–19, 2012 | 842 | ±3.4% | 49% | 45% | — | 6% |
| We Ask America | September 20–23, 2012 | 1,238 | ±2.8% | 52% | 40% | — | 8% |
| Marquette University | September 27–30, 2012 | 894 | ±3.3% | 48% | 44% | — | 6% |
| Public Policy Polling | October 4–6, 2012 | 979 | ±3.1% | 49% | 46% | — | 6% |
| CBS/NYT/Quinnipiac | October 4–9, 2012 | 1,327 | ±2.7% | 48% | 46% | — | 5% |
| Rasmussen Reports | October 9, 2012 | 500 | ±4.5% | 51% | 47% | 1% | 2% |
| YouGov | October 4–11, 2012 | 639 | ±4.9% | 48% | 43% | — | 9% |
| Marquette University | October 11–14, 2012 | 870 | ±3.3% | 45% | 46% | — | 7% |
| NBC/WSJ/Marist Poll | October 15–17, 2012 | 1,013 | ±3.1% | 49% | 45% | 1% | 5% |
| Mason-Dixon | October 15–17, 2012 | 625 | ±4% | 47% | 45% | — | 8% |
| Rasmussen Reports | October 18, 2012 | 500 | ±4.5% | 46% | 48% | 3% | 3% |
| Angus Reid Public Opinion | October 18–20, 2012 | 502 | ±4.5% | 45% | 42% | 3% | 11% |
| Rasmussen Reports | October 25, 2012 | 500 | ±4.5% | 47% | 48% | 2% | 4% |
| Marquette University | October 25–28, 2012 | 1,243 | ±2.8% | 47% | 43% | — | 10% |
| St. Norbert College | October 25–29, 2012 | 402 | ±5% | 43% | 46% | — | 11% |
| Rasmussen Reports | October 29, 2012 | 750 | ±4.0% | 48% | 48% | 1% | 2% |
| NBC/WSJ/Marist | October 31, 2012 | 1,065 | ±3.0% | 48% | 47% | 4% | 1% |
| WeAskAmerica | October 31 – November 1, 2012 | 1,210 | ±3% | 49% | 46% | — | 5% |
| YouGov | October 31 – November 3, 2012 | 1,225 | ±3.1% | 48% | 47% | — | 5% |
| Angus Reid Public Opinion | November 1–3, 2012 | 482 | ±4.5% | 50% | 48% | 2% | — |
| Public Policy Polling | November 2–3, 2012 | 1,256 | ±2.8% | 51% | 48% | — | 2% |
with Tammy Baldwin
| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin (D) | Jeff Fitzgerald (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 48% | 37% | — | 15% |
| Public Policy Polling | October 20–23, 2011 | 1,170 | ±2.9% | 44% | 40% | — | 16% |
| Rasmussen Reports | October 26, 2011 | 500 | ±4.5% | 46% | 39% | 4% | 6% |
| Marquette University | February 16–19, 2012 | 716 | ±3.7% | 45% | 37% | 3% | 15% |
| Public Policy Polling | February 23–26, 2012 | 900 | ±3.3% | 47% | 39% | — | 14% |
| Rasmussen Reports | February 27, 2012 | 500 | ±4.5% | 40% | 41% | 4% | 15% |
| Rasmussen Reports | March 27, 2012 | 500 | ±4.5% | 48% | 40% | 4% | 7% |
| Public Policy Polling | April 13–15, 2012 | 1,136 | ±2.9% | 47% | 40% | — | 13% |
| Rasmussen Reports | May 9, 2012 | 500 | ±4.5% | 45% | 41% | 4% | 9% |
| Rasmussen Reports | June 12, 2012 | 500 | ±4.5% | 44% | 43% | 5% | 8% |
| Marquette University | June 13–16, 2012 | 707 | ±3.8% | 45% | 39% | — | 16% |
| Public Policy Polling | July 5–8, 2012 | 1,057 | ±3.0% | 46% | 42% | — | 13% |
| Marquette University | July 5–8, 2012 | 810 | ±3.5% | 43% | 37% | — | 20% |
| Rasmussen Reports | July 25, 2012 | 500 | ±4.5% | 47% | 37% | 6% | 10% |
| Marquette University | August 2–5, 2012 | 1,400 | ±2.6% | 45% | 40% | — | 7% |
| Quinnipiac | July 31 – August 6, 2012 | 1,428 | ±2.6% | 51% | 39% | — | 9% |
| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin (D) | Eric Hovde (R) | Other | Undecided |
| Public Policy Polling | May 11–13, 2012 | 851 | ±3.4% | 41% | 45% | — | 14% |
| Rasmussen Reports | June 12, 2012 | 500 | ±4.5% | 42% | 44% | 4% | 10% |
| Marquette University | June 13–16, 2012 | 707 | ±3.8% | 45% | 36% | — | 19% |
| Public Policy Polling | July 5–8, 2012 | 1,057 | ±3.0% | 44% | 45% | — | 11% |
| Marquette University | July 5–8, 2012 | 810 | ±3.5% | 44% | 38% | — | 18% |
| Rasmussen Reports | July 25, 2012 | 500 | ±4.5% | 45% | 42% | 5% | 8% |
| Marquette University | August 2–5, 2012 | 1,400 | ±2.6% | 44% | 41% | — | 9% |
| Quinnipiac | July 31 – August 6, 2012 | 1,428 | ±2.6% | 47% | 43% | 1% | 8% |
| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin (D) | Mark Neumann (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 46% | 41% | — | 13% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 40% | 44% | — | 15% |
| Public Policy Polling | October 20–23, 2011 | 1,170 | ±2.9% | 44% | 43% | — | 13% |
| Rasmussen Reports | October 26, 2011 | 500 | ±4.5% | 44% | 43% | 4% | 9% |
| Marquette University | February 16–19, 2012 | 716 | ±3.7% | 44% | 40% | 2% | 14% |
| Public Policy Polling | February 23–26, 2012 | 900 | ±3.3% | 47% | 41% | — | 12% |
| Rasmussen Reports | February 27, 2012 | 500 | ±4.5% | 37% | 46% | 4% | 13% |
| Rasmussen Reports | March 27, 2012 | 500 | ±4.5% | 48% | 40% | 4% | 8% |
| Public Policy Polling | April 13–15, 2012 | 1,136 | ±2.9% | 46% | 45% | — | 9% |
| Rasmussen Reports | May 9, 2012 | 500 | ±4.5% | 42% | 44% | 4% | 9% |
| Public Policy Polling | May 11–13, 2012 | 851 | ±3.4% | 42% | 46% | — | 12% |
| Rasmussen Reports | June 12, 2012 | 500 | ±4.5% | 43% | 45% | 5% | 7% |
| Marquette University | June 13–16, 2012 | 707 | ±3.8% | 44% | 44% | — | 12% |
| Public Policy Polling | July 5–8, 2012 | 1,057 | ±3.0% | 45% | 41% | — | 13% |
| Marquette University | July 5–8, 2012 | 810 | ±3.5% | 43% | 40% | — | 17% |
| Rasmussen Reports | July 25, 2012 | 500 | ±4.5% | 48% | 42% | 3% | 8% |
| Marquette University | August 2–5, 2012 | 1,400 | ±2.6% | 44% | 44% | — | 6% |
| Quinnipiac | July 31 – August 6, 2012 | 1,428 | ±2.6% | 48% | 45% | 1% | 6% |
| Poll source | Date(s) administered | Sample size | Margin of error | Tammy Baldwin (D) | J. B. Van Hollen (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 46% | 39% | — | 15% |
with Russ Feingold
| Poll source | Date(s) administered | Sample size | Margin of error | Russ Feingold (D) | Jeff Fitzgerald (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 55% | 39% | — | 7% |
| Poll source | Date(s) administered | Sample size | Margin of error | Russ Feingold (D) | Mark Neumann (R) | Other | Undecided |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 51% | 44% | — | 5% |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 53% | 41% | — | 6% |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 50% | 40% | — | 10% |
| Poll source | Date(s) administered | Sample size | Margin of error | Russ Feingold (D) | Paul Ryan (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 50% | 43% | — | 7% |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 49% | 42% | — | 9% |
| Poll source | Date(s) administered | Sample size | Margin of error | Russ Feingold (D) | Tommy Thompson (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 49% | 40% | — | 11% |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 52% | 42% | — | 6% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 48% | 47% | — | 5% |
| Poll source | Date(s) administered | Sample size | Margin of error | Russ Feingold (D) | J. B. Van Hollen (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 52% | 41% | — | 7% |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 51% | 39% | — | 10% |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 53% | 38% | — | 9% |
with Steve Kagen
| Poll source | Date(s) administered | Sample size | Margin of error | Steve Kagen (D) | Jeff Fitzgerald (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 43% | 38% | — | 19% |
| Poll source | Date(s) administered | Sample size | Margin of error | Steve Kagen (D) | Mark Neumann (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 42% | 41% | — | 17% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 38% | 45% | — | 17% |
| Poll source | Date(s) administered | Sample size | Margin of error | Steve Kagen (D) | Tommy Thompson (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 42% | 45% | — | 13% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 41% | 49% | — | 10% |
| Poll source | Date(s) administered | Sample size | Margin of error | Steve Kagen (D) | J. B. Van Hollen (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 43% | 38% | — | 19% |
with Ron Kind
| Poll source | Date(s) administered | Sample size | Margin of error | Ron Kind (D) | Jeff Fitzgerald (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 45% | 37% | — | 18% |
| Poll source | Date(s) administered | Sample size | Margin of error | Ron Kind (D) | Mark Neumann (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 44% | 40% | — | 16% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 40% | 43% | — | 17% |
| Poll source | Date(s) administered | Sample size | Margin of error | Ron Kind (D) | Tommy Thompson (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 44% | 44% | — | 12% |
| Public Policy Polling | August 12–14, 2011 | 830 | ±3.4% | 41% | 48% | — | 11% |
| Poll source | Date(s) administered | Sample size | Margin of error | Ron Kind (D) | J. B. Van Hollen (R) | Other | Undecided |
| Public Policy Polling | May 19–22, 2011 | 1,636 | ±2.4% | 44% | 38% | — | 17% |
with Herb Kohl
| Poll source | Date(s) administered | Sample size | Margin of error | Herb Kohl (D) | Mark Neumann (R) | Other | Undecided |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 51% | 37% | — | 12% |
| Poll source | Date(s) administered | Sample size | Margin of error | Herb Kohl (D) | Paul Ryan (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 48% | 42% | — | 11% |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 49% | 42% | — | 10% |
| Poll source | Date(s) administered | Sample size | Margin of error | Herb Kohl (D) | Tommy Thompson (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 49% | 40% | — | 11% |
| Poll source | Date(s) administered | Sample size | Margin of error | Herb Kohl (D) | J. B. Van Hollen (R) | Other | Undecided |
| Public Policy Polling | December 10–12, 2010 | 702 | ±3.7% | 51% | 38% | — | 11% |
| Public Policy Polling | February 24–27, 2011 | 768 | ±3.5% | 52% | 37% | — | 11% |

### Results

United States Senate election in Wisconsin, 2012 :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Tammy Baldwin | 1,547,104 | 51.41% | −15.90% |
| | Republican | Tommy Thompson | 1,380,126 | 45.86% | +16.38% |
| | Libertarian | Joseph Kexel | 62,240 | 2.07% | N/A |
| | Independent | Nimrod Allen, III | 16,455 | 0.55% | N/A |
| | Write-in | Write-in | 3,486 | 0.11% | +0.05% |
| Total votes | Total votes | Total votes | 3,009,411 | 100.00% | N/A |
| | Democratic hold | Democratic hold | Democratic hold | Democratic hold | Democratic hold |

#### Counties that flipped Democratic to Republican

* Barron (largest city: Rice Lake)
* Brown (largest city: Green Bay)
* Burnett (largest village: Grantsburg)
* Calumet (largest city: Chilton)
* Clark (largest city: Neillsville)
* Iron (largest city: Hurley)
* Jefferson (largest city: Watertown)
* Kewaunee (largest city: Algoma)
* Langlade (largest city: Antigo)
* Manitowoc (largest city: Manitowoc)
* Marathon (largest city: Wausau)
* Marinette (largest city: Marinette)
* Monroe (largest city: Sparta)
* Oconto (largest city: Oconto)
* Oneida (largest city: Rhinelander)
* Outagamie (largest city: Appleton)
* Rusk (largest city: Ladysmith)
* Shawano (largest city: Shawano)
* Washburn (largest city: Spooner)
* Waupaca (largest city: New London)
* Waushara (largest city: Berlin)
* Adams (largest city: Adams)
* Marquette (largest city: Montello)
* Polk (Largest city: Amery)
* Sheboygan (Largest city: Sheboygan)
* St. Croix (Largest city: Hudson)
* Taylor (Largest city: Medford)
* Florence (Largest city: Florence)
* Vilas (Largest city: Eagle River)
* Fond du Lac (Largest city: Fond du Lac)
* Green Lake (Largest city: Green Lake)
* Dodge (Largest city: Juneau)
* Ozaukee (Largest city: Mequon)
* Walworth (Largest city: Whitewater)
* Washington (Largest city: West Bend)
* Waukesha (Largest city: Waukesha)

#### By congressional district

Despite losing the state, Thompson won 5 of 8 congressional districts.
| District | Thompson | Baldwin | Representative |
| 1st | 50.61% | 46.56% | Paul Ryan |
| 2nd | 32.28% | 65.82% | Mark Pocan |
| 3rd | 44.31% | 52.77% | Ron Kind |
| 4th | 25.15% | 72.93% | Gwen Moore |
| 5th | 61.06% | 36.68% | Jim Sensenbrenner |
| 6th | 52.93% | 44.05% | Tom Petri |
| 7th | 48.93% | 48.06% | Sean Duffy |
| 8th | 50.21% | 46.63% | Reid Ribble |

## Aftermath

Brian Schimming, the vice chairman of the Wisconsin Republican Party, partly blamed Thompson's defeat on the fact that he had to face a competitive primary whereas Baldwin was unopposed for the Democratic nomination: "[Thompson] blew all his money going through the primary. So when he gets through the primary, it was like three weeks before he was up on the air. [Baldwin] piled on immediately." He claimed "If [Thompson] hadn't had as ugly a primary, we could have won that seat."