2018 United States Senate election in Montana

The 2018 United States Senate election in Montana was held on November 6, 2018, to elect a member of the United States Senate to represent the State of Montana, concurrently with other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections.

This was one of ten Democratic-held Senate seats up for election in a state that Donald Trump won in the 2016 presidential election. Incumbent Democratic Senator Jon Tester was reelected to a third term, defeating Republican State Auditor Matt Rosendale. Rosendale conceded on November 7, 2018.Rosendale congratulates Sen. Tester on his victory, KULR, November 7, 2018. Retrieved November 8, 2018. This was the first and only Senate election in which Tester received a majority of votes. As of 2026, this is the last time Democrats won a congressional and/or statewide election in Montana.

Following his loss, Rosendale went on to run for Montana's vacant congressional seat in 2020 and won, taking office in the U.S. House of Representatives in January 2021.

Democratic primary Candidates Nominated Jon Tester, incumbent U.S. senator

Endorsements

Results

Republican primary Candidates Nominated Matt Rosendale, auditor of Montana and candidate for Congress in 2014

Eliminated in primary Troy Downing, veteran and businessman Russell Fagg, former Yellowstone County district judge Albert Olszewski, state senator and candidate for lieutenant governor in 2012

Withdrew Ron Murray, businessman and candidate for the state house in 2010

Declined Tim Fox, attorney general of Montana Robert J. O'Neill, former Navy SEAL (endorsed Troy Downing) Marc Racicot, former governor and former chairman of the Republican National Committee (endorsed Russell Fagg) Corey Stapleton, Secretary of State of Montana, candidate for governor in 2012 and candidate for Congress in 2014 Ryan Zinke, former Secretary of the Interior and former U.S. representative

Endorsements

Polling Poll source Date(s)administered Samplesize Marginof error TroyDowning RussellFagg AlOlszewski MattRosendale Other UndecidedWPA Intelligence (R-Club for Growth)WPA Intelligence (R-Club for Growth) April 15–16, 2018 503 ± 4.4% 12% 17% 8% 40% – 23%WPA Intelligence (R-Rosendale)WPA Intelligence (R-Rosendale) February 5–7, 2018 401 ± 4.4% 12% 11% 5% 28% 1%Ron Murray 1% –

Results

Libertarian primary Candidates Nominated Rick Breckenridge, 2016 candidate for the U.S. House of RepresentativesDrake, Phil (March 5, 2018). "Libertarian says he'll enter Montana U.S. Senate race". Great Falls Tribune. Retrieved March 5, 2018.

In October 2018, Breckenridge told a reporter from the Associated Press that he opposed the use of dark money in politics. Breckenridge said that he realistically anticipated only receiving three or four percent of the vote in the general election, and that he endorsed Rosendale's efforts to stop the use of dark money in politics. The Associated Press interpreted Breckenridge's comments as a statement that Breckenridge was dropping out of the race and endorsing Rosendale. Breckenridge later stated that his use of the word "endorse" referred only to stopping the use of dark money in politics, and said he was still running for the Senate.Doherty, Brian (October 31, 2018). "Despite Donald Trump Jr. Retweet, Libertarian Senate Candidate Rick Breckenridge Did Not Drop Out". Reason.Barber, Ellison; O'Reilly, Andrew (November 6, 2018). "Montana Libertarian candidate walks back endorsement of GOP nominee Rosendale in tight Senate race". Fox News.

Green Party Kelly won the Green Party nomination, but a Montana district court judge ruled that he had insufficient signatures to get on the ballot.

Candidates Nominee (removed from ballot) Steve Kelly, artist and environmental activist

Eliminated in primary Timothy Adams

Results

General election

Debates Complete video of debate, C-SPAN September 29, 2018 Complete video of debate, YouTube October 14, 2018

Predictions SourceRankingAs ofThe Cook Political Report October 26, 2018Inside Elections November 1, 2018Sabato's Crystal BallNovember 5, 2018Daily KosNovember 1, 2018Fox NewsNovember 1, 2018CNNNovember 1, 2018RealClearPoliticsNovember 5, 2018FiveThirtyEightNovember 6, 2018

Endorsements

Fundraising Campaign finance reports as of October 17, 2018Candidate (party)Total receiptsTotal disbursementsCash on handJon Tester (D)$19,499,290$17,946,600$1,612,530Matt Rosendale (R)$5,034,075$4,515,910$524,379Rick Breckenridge (L)---Source: Federal Election Commission

Polling

Poll source Date(s)administered Samplesize Marginof error JonTester (D) MattRosendale (R) Rick Other UndecidedThe Trafalgar Group (R)The Trafalgar Group (R) November 2–5, 2018 953 ± 3.2% 50% 49% – 1% 0%HarrisXHarrisX November 1–5, 2018 500 ± 4.4% 50% 42% – – –Change ResearchChange Research November 2–4, 2018 879 – 46% 49% 3% – –HarrisXHarrisX October 31 – November 4, 2018 500 ± 4.4% 49% 43% – – –HarrisX October 30 – November 3, 2018 500 ± 4.4% 49% 43% – – –HarrisX October 29 – November 2, 2018 500 ± 4.4% 50% 42% – – –HarrisX October 28 – November 1, 2018 500 ± 4.4% 49% 42% – – –HarrisX October 27–31, 2018 500 ± 4.4% 49% 42% – – –HarrisXHarrisX October 24–30, 2018 700 ± 3.7% 48% 40% – – –Gravis MarketingGravis Marketing October 24–26, 2018 782 ± 3.5% 48% 45% – – 7%University of MontanaUniversity of Montana October 10–18, 2018 533 ± 4.3% 49% 39% 2% – 10%Montana State University BillingsMontana State University Billings October 8–13, 2018 471 ± 4.5% 47% 38% 3% – 12%Montana State University BozemanMontana State University Bozeman September 15 – October 6, 2018 2,079 ± 2.2% 46% 43% 3% 2% 7%Public Policy Polling (D-Protect Our Care)Public Policy Polling (D-Protect Our Care) September 28, 2018 594 ± 4.0% 49% 45% – – 6%Gravis MarketingGravis Marketing September 19–22, 2018 710 ± 3.7% 49% 45% – – 6%Axis Research (R-NRSC)Axis Research (R-NRSC) September 17–19, 2018 – ± 4.5% 44% 44% 4% – 8%AARP/Benenson Strategy Group (D) September 6–16, 2018 950 ± 3.1% 50% 43% – 2% 5%CBS News/YouGovCBS News/YouGov September 10–14, 2018 453 – 47% 45% – 3% 5%University of MontanaUniversity of Montana August 13–31, 2018 466 ± 4.5% 56% 32% 2% – 9%WPA Intelligence (R-NRSC)WPA Intelligence (R-NRSC) August 20–22, 2018 600 ± 4.0% 45% 47% – – 5%Remington Research (R)Remington Research (R) July 8–10, 2018 2,581 ± 2.0% 49% 46% – – 5%SurveyMonkey/AxiosSurveyMonkey/Axios June 11 – July 2, 2018 974 ± 5.0% 55% 43% – – 3%Gravis MarketingGravis Marketing June 11–13, 2018 469 ± 4.5% 52% 44% – – 4%

Poll source Date(s)administered Samplesize Marginof error JonTester (D) GenericRepublican UndecidedSurveyMonkey/AxiosSurveyMonkey/Axios February 12–March 5, 2018 1,484 ± 3.4% 42% 55% 3%

Results

By county From Secretary of State of Montana CountyJon TesterDemocraticMatt RosendaleRepublicanRick BreckenridgeLibertarian Total votes#%#%#%Beaverhead1,876 38.31%2,86658.53%155 3.17%4,897Big Horn3,02764.73%1,558 33.32%91 1.95%4,676Blaine1,96164.96%982 32.53%76 2.52%3,019Broadwater1,071 32.84%2,08663.97%104 3.19%3,261Carbon2,680 44.17%3,20952.89%178 2.93%6,067Carter128 17.02%60280.05%22 2.93%752Cascade17,43551.27%15,566 45.77%1,008 2.96%34,009Chouteau1,275 47.99%1,31249.38%70 2.63%2,657Custer1,942 39.77%2,76256.56%179 3.67%4,883Daniels281 29.86%63167.06%29 3.08%941Dawson1,233 30.27%2,70066.29%140 3.44%4,073Deer Lodge2,89268.27%1,208 28.52%136 3.21%4,236Fallon281 21.80%95173.78%57 4.42%1,289Fergus1,964 33.90%3,64062.83%189 3.26%5,793Flathead19,652 41.15%26,75956.03%1,349 2.82%47,760Gallatin33,25159.45%21,248 37.99%1,434 2.56%55,933Garfield81 11.88%57183.72%30 4.40%682Glacier3,75475.14%1,153 23.08%89 1.78%4,996Golden Valley130 28.63%30366.74%21 4.63%454Granite695 38.76%1,04658.34%52 2.90%1,793Hill3,72958.36%2,434 38.09%227 3.55%6,390Jefferson2,954 43.23%3,65353.46%226 3.31%6,833Judith Basin388 32.58%75263.14%51 4.28%1,191Lake6,91650.22%6,491 47.13%365 2.65%13,772Lewis and Clark20,50657.70%14,106 39.69%927 2.61%35,539Liberty365 37.21%58659.73%30 3.06%981Lincoln2,902 31.08%6,13765.73%298 3.19%9,337Madison1,890 38.11%2,89858.44%171 3.45%4,959McCone227 22.06%77375.12%29 2.82%1,029Meagher319 32.68%62964.45%28 2.87%976Mineral785 38.14%1,18157.39%92 4.47%2,058Missoula41,68867.62%18,631 30.22%1,332 2.16%61,651Musselshell573 23.56%1,74371.67%116 4.77%2,432Park5,11452.59%4,357 44.81%253 2.60%9,724Petroleum58 18.59%24879.49%6 1.92%312Phillips577 27.71%1,42668.49%79 3.79%2,082Pondera1,176 43.80%1,41352.63%96 3.58%2,685Powder River203 20.86%74876.88%22 2.26%973Powell1,026 37.17%1,64159.46%93 3.37%2,760Prairie177 27.11%45068.91%26 3.98%653Ravalli9,156 39.13%13,62258.21%623 2.66%23,401Richland1,136 26.22%3,01769.64%179 4.13%4,332Roosevelt2,01358.40%1,346 39.05%88 2.55%3,447Rosebud1,511 44.88%1,76552.42%91 2.70%3,367Sanders2,071 33.65%3,85662.66%227 3.69%6,154Sheridan712 39.29%1,01756.13%83 4.58%1,812Silver Bow11,67271.55%4,246 26.03%394 2.42%16,312Stillwater1,501 30.86%3,20665.91%157 3.23%4,864Sweet Grass652 31.08%1,37265.40%74 3.53%2,098Teton1,290 40.86%1,78456.51%83 2.63%3,157Toole626 32.90%1,20863.48%69 3.63%1,903Treasure129 31.16%27967.39%6 1.45%414Valley1,545 39.80%2,13755.05%200 5.15%3,882Wheatland315 33.76%58662.81%32 3.43%933Wibaux140 25.83%39071.96%12 2.21%542Yellowstone32,225 46.53%34,68250.08%2,351 3.39%69,258

Counties that flipped from Democratic to Republican Chouteau (largest municipality: Fort Benton) Rosebud (largest municipality: Colstrip) Yellowstone (largest municipality: Billings)

References

External links Candidates at Vote Smart Candidates at Ballotpedia Campaign finance at FEC Campaign finance at OpenSecrets

Official campaign websites Matt Rosendale (R) for Senate Jon Tester (D) for Senate