The 2018 United States Senate election in Indiana took place on November 6, 2018, along with other elections to the United States Senate and House of Representatives and various state and local elections. Incumbent Democratic Senator Joe Donnelly ran for re-election to a second term, however, he lost in the general election to Republican Mike Braun by a margin of 6%. This was the second consecutive election for this seat in which the incumbent was defeated and/or the seat flipped parties.

This was one of ten Democratic-held Senate seats up for election in a state won by Donald Trump in the 2016 presidential election. In 2017, Politico described the race as "possibly the GOP's best opportunity to seize a Senate seat from Democrats" in the 2018 elections. The primary election was held on May 8, 2018. In October 2018, RealClearPolitics rated the race a toss-up between the Democratic and Republican nominees, with the Libertarian receiving a poll average of 6%.

Instead of running for a second senatorial term in 2024, Braun campaigned successfully to become Governor of Indiana.

Background In 2012, Joe Donnelly was elected to the Senate with 50% of the vote to Republican nominee Richard Mourdock's 44%. In the 2016 presidential election, Republican nominee Donald Trump won Indiana with about 56.5% of the vote to Democratic nominee Hillary Clinton's 37.5%.

Democratic primary Candidates Nominee Joe Donnelly, incumbent U.S. senator

Withdrew Martin Del Rio, Iraq War veteran

Endorsements

Results

Republican primary Candidates Nominee Mike Braun, businessman and former state representative

Eliminated in the primary election Luke Messer, U.S. representative Todd Rokita, U.S. representative

Declined Jim Banks, U.S. representative Susan Brooks, U.S. representative (endorsed Luke Messer) Mike Delph, state senator (endorsed Todd Rokita) Jackie Walorski, U.S. representative

Withdrawn Terry Henderson, businessman (endorsed Mike Braun) Andy Horning, Libertarian nominee for the U.S. Senate in 2012 and Libertarian nominee for IN-08 in 2014 Mark Hurt, attorney and former congressional aide Andrew Takami, director of Purdue Polytechnic New Albany (endorsed Luke Messer)

Endorsements

Polling Poll source Date(s)administered Samplesize Marginof error LukeMesser ToddRokita MikeBraun Other UndecidedStrategic National (R)Strategic National (R) May 5–6, 2018 300 ± 5.7% 29% 28% 44% – –Gravis MarketingGravis Marketing April 6–11, 2018 280 ± 5.9% 13% 16% 26% – 45%GS Strategy Group (R-Rokita)GS Strategy Group (R-Rokita) January 6–9, 2018 500 ± 4.4% 9% 24% 9% – 58%GS Strategy Group (R-Rokita)GS Strategy Group (R-Rokita) July 16–18, 2017 500 ± 4.4% 20% 28% – – 51% 14% 21% 11% – 55%OnMedia (R-Messer)OnMedia (R-Messer) July 10–12, 2017 400 ± 4.8% 23% 23% 2% 7% 45%

Results

Independent

Candidates Declared James Johnson Jr.

General election Candidates Mike Braun, businessman and former state representative (R) Lucy Brenton (L) Joe Donnelly, incumbent (D) James Johnson Jr. (I)

Debates Complete video of debate, October 8, 2018

Predictions SourceRankingAs ofThe Cook Political Report October 26, 2018Inside Elections November 1, 2018Sabato's Crystal BallNovember 5, 2018CNN November 5, 2018RealClearPolitics November 5, 2018Daily Kos November 5, 2018Fox News November 5, 2018FiveThirtyEight November 5, 2018

Fundraising Campaign finance reports as of October 17, 2018Candidate (party)Total receiptsTotal disbursementsCash on handJoe Donnelly (D)$16,100,528$13,872,981$2,321,981Mike Braun (R)$16,964,706$15,576,842$1,387,861Source: Federal Election Commission

Endorsements

Polling Graphical summary

Poll source Date(s)administered Samplesize Marginof error JoeDonnelly (D) MikeBraun (R) LucyBrenton (L) Other UndecidedHarrisXHarrisX November 3–5, 2018 600 ± 4.0% 42% 43% – – –HarrisXHarrisX November 2–4, 2018 600 ± 4.0% 43% 41% – – –HarrisX November 1–3, 2018 600 ± 4.0% 43% 42% – – –HarrisX October 31 – November 2, 2018 600 ± 4.0% 44% 42% – – –HarrisX October 30 – November 1, 2018 600 ± 4.0% 43% 43% – – –HarrisX October 29–31, 2018 600 ± 4.0% 40% 43% – – –Fox NewsFox News October 27–30, 2018 722 LV ± 3.5% 45% 38% 5% 2% 9% 852 RV ± 3.0% 42% 38% 6% 2% 11%HarrisXHarrisX October 24–30, 2018 1,400 ± 2.6% 42% 42% – – –NBC News/MaristNBC News/Marist October 24–28, 2018 496 LV ± 5.5% 45% 42% 7% <1% 5% 48% 46% – 2% 5% 800 RV ± 4.2% 43% 40% 9% <1% 7% 47% 45% – 2% 7%Cygnal (R)Cygnal (R) October 26–27, 2018 505 ± 4.4% 46% 49% – 3% 2%YouGovYouGov October 23–26, 2018 975 ± 3.7% 43% 46% 3% 0% 8%Mason Strategies (R)Mason Strategies (R) October 15–20, 2018 600 ± 3.9% 43% 47% 3% – 7%American Viewpoint (R-Braun)American Viewpoint (R-Braun) October 14–17, 2018 800 – 40% 44% 7% – 5%SurveyUSASurveyUSA October 12–16, 2018 816 ± 4.6% 41% 40% 8% – 11%Gravis MarketingGravis Marketing October 12–16, 2018 377 ± 5.1% 44% 40% 7% – 10%Vox Populi Polling October 13–15, 2018 783 ± 3.5% 55% 45% – – –American Viewpoint (R-Braun) October 7–10, 2018 800 – 40% 44% 7% – 7%American Viewpoint (R-Braun) September 30 – October 3, 2018 800 – 39% 43% 7% – 5%Fox NewsFox News September 29 – October 2, 2018 695 LV ± 3.5% 43% 41% 6% 2% 9% 806 RV ± 3.5% 41% 40% 6% 1% 10%IpsosIpsos September 12–20, 2018 1,181 ± 3.0% 46% 43% – 3% 8%Fox NewsFox News September 8–11, 2018 677 LV ± 3.5% 43% 45% 3% 1% 8% 804 RV ± 3.5% 42% 41% 4% 1% 10%NBC News/MaristNBC News/Marist August 26–29, 2018 576 LV ± 5.0% 44% 41% 8% 1% 6% 49% 43% – 2% 7% 816 RV ± 4.2% 43% 40% 8% 1% 8% 48% 42% – 2% 9%Trafalgar Group (R)Trafalgar Group (R) July 31 – August 7, 2018 1,420 ± 2.6% 51% 39% – – 11%SurveyMonkey/AxiosSurveyMonkey/Axios June 11 – July 2, 2018 952 ± 5.0% 47% 49% – – 4%Gravis MarketingGravis Marketing May 10–15, 2018 400 ± 4.9% 46% 47% – – 7%

with Todd Rokita Poll source Date(s)administered Samplesize Marginof error JoeDonnelly (D) ToddRokita (R) UndecidedGravis Marketing April 6–11, 2018 411 ± 4.8% 50% 32% 18%

with Luke Messer Poll source Date(s)administered Samplesize Marginof error JoeDonnelly (D) LukeMesser (R) UndecidedGravis Marketing April 6–11, 2018 411 ± 4.8% 46% 36% 18%

with generic Republican Poll source Date(s)administered Samplesize Marginof error JoeDonnelly (D) GenericRepublican UndecidedSurveyMonkey/AxiosSurveyMonkey/Axios February 12 – March 5, 2018 1,809 ± 3.8% 45% 51% 4%

Results

On November 6, 2018, Braun won the general election. He swept southern Indiana, the exurbs of Indianapolis, and most other rural areas in the state. Donnelly ran well behind his 2012 vote totals, winning only in Indianapolis, the university centers (Bloomington, Terre Haute, West Lafayette, South Bend), and the suburbs of Chicago in Northwest Indiana.

By county Source

County Mike BraunRepublican Joe DonnellyDemocratic Lucy BrentonLibertarian Margin Total Votes % Votes % Votes % Votes %Adams7,51167.39%3,14628.23%4894.39%4,36539.16%11,146Allen65,92752.36%55,90344.40%4,0803.24%10,0247.96%125,910Bartholomew15,22257.41%10,07137.98%1,2234.61%5,15119.43%26,516Benton1,92664.98%84728.58%1916.44%1,07936.40%2,964Blackford2,30359.39%1,27532.88%3007.74%1,02826.51%3,878Boone15,54056.43%10,98139.87%1,0193.70%4,55916.55%27,540Brown4,10357.07%2,76838.50%3184.42%1,33518.57%7,189Carroll4,51865.35%2,07129.95%3254.70%2,44735.39%6,914Cass6,61757.79%4,06135.47%7726.74%2,55622.32%11,450Clark22,76652.60%18,55142.86%1,9674.54%4,2159.74%43,284Clay6,20766.91%2,60128.04%4695.06%3,60638.87%9,277Clinton5,96764.81%2,75529.92%4855.27%3,21234.89%9,207Crawford2,25256.83%1,50437.95%2075.22%74818.87%3,963Daviess6,55575.01%1,90121.75%2833.24%4,65453.26%8,739Dearborn13,28772.79%4,48124.55%4872.67%8,80648.24%18,255Decatur6,24669.35%2,28725.39%4735.25%3,95943.96%9,006DeKalb9,16765.80%4,20430.18%5614.03%4,96335.62%13,932Delaware17,44746.27%18,15948.16%2,0995.57%-712-1.89%37,705Dubois11,20465.42%5,26430.74%6583.84%5,94034.68%17,126Elkhart31,16457.83%21,06239.09%1,6613.08%10,10218.75%53,887Fayette4,70463.02%2,29530.75%4656.23%2,40932.27%7,464Floyd16,58852.12%14,07044.21%1,1673.67%2,5187.91%31,825Fountain4,06069.18%1,49625.49%3135.33%2,56443.69%5,869Franklin5,61475.54%1,61921.78%1992.68%3,99553.75%7,432Fulton4,15459.28%2,53936.23%3154.49%1,61523.05%7,008Gibson8,04064.26%4,00131.98%4713.76%4,03932.28%12,512Grant12,39361.76%6,74533.61%9294.63%5,64828.15%20,067Greene6,94964.50%3,31330.75%5114.74%3,63633.75%10,773Hamilton72,32552.38%61,33744.42%4,4103.19%10,9887.96%138,072Hancock19,09763.10%9,77032.28%1,3994.62%9,32730.82%30,266Harrison9,84763.05%5,13132.86%6394.09%4,71630.20%15,617Hendricks36,96658.85%23,59937.57%2,2473.58%13,36721.28%62,812Henry9,56960.98%5,17132.95%9536.07%4,39828.03%15,693Howard16,73657.18%11,15938.12%1,3764.70%5,57719.05%29,271Huntington8,87967.22%3,69928.00%6314.78%5,18039.22%13,209Jackson9,43165.43%4,19829.12%7855.45%5,23336.30%14,414Jasper6,98766.00%3,27830.97%3213.03%3,70935.04%10,586Jay3,99063.42%1,93330.73%3685.85%2,05732.70%6,291Jefferson6,34556.44%4,31338.37%5845.19%2,03218.08%11,242Jennings5,92164.72%2,68629.36%5425.92%3,23535.36%9,149Johnson32,54062.70%17,47933.68%1,8833.63%15,06129.02%51,902Knox7,87662.38%3,97731.50%7726.11%3,89930.88%12,625Kosciusko18,55870.34%6,80125.78%1,0223.87%11,75744.57%26,381LaGrange5,18367.49%2,21728.87%2803.65%2,96638.62%7,680Lake54,56433.62%104,39064.32%3,3402.06%-49,826-30.70%162,294LaPorte16,00842.98%20,01453.73%1,2253.29%-4,006-10.76%37,247Lawrence10,27466.30%4,43428.61%7885.09%5,84037.69%15,496Madison22,84151.83%18,70142.44%2,5265.73%4,1409.39%44,068Marion98,38532.04%197,88064.43%10,8403.53%-99,495-32.40%307,105Marshall8,74758.71%5,61937.71%5333.58%3,12820.99%14,899Martin2,99769.31%1,12726.06%2004.63%1,87043.25%4,324Miami6,97567.30%2,86227.61%5275.08%4,11339.69%10,364Monroe15,54029.94%34,19365.87%2,1744.19%-18,653-35.94%51,907Montgomery8,36266.69%3,51828.06%6595.26%4,84438.63%12,539Morgan17,53969.72%6,47125.72%1,1484.56%11,06843.99%25,158Newton2,96665.00%1,40230.73%1954.27%1,56434.28%4,563Noble8,99365.70%4,13230.18%5644.12%4,86135.51%13,689Ohio1,58666.22%74731.19%622.59%83935.03%2,395Orange4,35364.28%2,13531.53%2844.19%2,21832.75%6,772Owen4,60163.96%2,21030.72%3835.32%2,39133.24%7,194Parke3,53266.12%1,49928.06%3115.82%2,03338.06%5,342Perry3,45048.25%3,36447.04%3374.71%861.20%7,151Pike3,23562.71%1,67932.55%2454.75%1,55630.16%5,159Porter29,36845.32%33,39051.53%2,0373.14%-4,022-6.21%64,795Posey6,32459.44%3,88136.48%4354.09%2,44322.96%10,640Pulaski2,58359.26%1,61737.10%1593.65%96622.16%4,359Putnam7,81465.67%3,51229.52%5734.82%4,30236.15%11,899Randolph5,13863.35%2,46730.42%5056.23%2,67132.93%8,110Ripley6,88072.66%2,35024.82%2392.52%4,53047.84%9,469Rush3,99165.61%1,69027.78%4026.61%2,30137.83%6,083St. Joseph36,45639.08%53,75857.63%3,0733.29%-17,302-18.55%93,287Scott4,24155.34%3,11340.62%3094.03%1,12814.72%7,663Shelby9,34064.78%4,33330.05%7455.17%5,00734.73%14,418Spencer5,20258.61%3,21836.26%4555.13%1,98422.35%8,875Starke4,14954.71%3,11941.13%3164.17%1,03013.58%7,584Steuben7,83964.39%3,86431.74%4723.88%3,97532.65%12,175Sullivan4,34058.66%2,66336.00%3955.34%1,67722.67%7,398Switzerland1,87464.07%93632.00%1153.93%93832.07%2,925Tippecanoe22,64944.02%26,37651.26%2,4314.72%-3,727-7.24%51,456Tipton4,06266.30%1,73428.30%3315.40%2,32838.00%6,127Union1,74969.85%68227.24%732.92%1,06742.61%2,504Vanderburgh29,37550.20%27,18346.45%1,9623.35%2,1923.75%58,520Vermillion3,00253.68%2,19839.31%3927.01%80414.38%5,592Vigo14,81346.79%15,17147.92%1,6745.29%-358-1.13%31,658Wabash7,65867.78%3,15927.96%4824.27%4,49939.82%11,299Warren2,20867.34%91427.87%1574.79%1,29439.46%3,279Warrick14,01057.50%9,59439.37%7623.13%4,41618.12%24,366Washington6,12765.31%2,80629.91%4484.78%3,32135.40%9,381Wayne11,24156.88%7,48237.86%1,0395.26%3,75919.02%19,762Wells7,81971.79%2,69424.73%3793.48%5,12547.05%10,892White5,10060.05%2,73932.25%6547.70%2,36127.80%8,493Whitley9,01967.39%3,81828.53%5474.09%5,20138.86%13,384 Counties that flipped from Democratic to Republican Madison (largest city: Anderson) Spencer (largest city: Santa Claus) Starke (largest city: Knox)