The 2018 United States Senate election in Missouri took place on November 6, 2018, to elect a member of the United States Senate to represent the State of Missouri, concurrently with other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections, including Missouri's quadrennial State Auditor election.
This was one of ten Democratic-held Senate seats up for election in a state Donald Trump won in the 2016 presidential election. Incumbent Democratic Senator Claire McCaskill ran for re-election to a third term. McCaskill easily won her party's nomination, defeating several minor candidates in the primary, while Missouri Attorney General Josh Hawley comfortably won the Republican primary.
The candidate filing deadline was March 27, 2018, and the primary election was held on August 7, 2018. Pollsters predicted a tight race; however, Hawley defeated McCaskill on election day by 5.8%, taking 51.4% of the vote to McCaskill's 45.6%, a somewhat larger margin than expected. This resulted in Republicans holding both Senate seats in Missouri for the first time since McCaskill took office in 2007. Hawley was also the youngest incumbent senator at that time, and continued to be until the inauguration of Jon Ossoff in 2021. Despite her loss, McCaskill outperformed Hillary Clinton's performance in the state in the 2016 presidential race. This is the last U.S. Senate race in Missouri where the incumbent was defeated.
Democratic primary Candidates Nominated Claire McCaskill, incumbent U.S. Senator
Eliminated in primary Angelica Earl, former insurance verification specialist David Faust Travis Gonzalez, perennial candidate John Hogan, perennial candidate Leonard Steinman, perennial candidate Carla (Coffee) Wright
Endorsements
Results
Republican primary Candidates Nominated Josh Hawley, Missouri Attorney General
Eliminated in primary Brian Hagg Bradley Krembs Tony Monetti, retired bomber pilot and assistant dean of aviation at University of Central Missouri Kristi Nichols, activist and candidate for the U.S. Senate in 2010 and 2016 Ken Patterson, candidate for St. Louis County Executive in 2010 Austin Petersen, businessman and Libertarian candidate for presidential nomination in 2016 Peter Pfeifer Fred Ryman, Constitution nominee for the U.S. Senate in 2016 Christina Smith Courtland Sykes, veteran and former congressional aide
Withdrew Camille Lombardi-Olive, Democratic candidate for MO-07 in 2016
Declined Paul Curtman, state representative Eric Greitens, former Governor of Missouri Marsha Haefner, state representative Vicky Hartzler, U.S. representative Aaron Hedlund, economics professor Ed Martin, former chairman of the Missouri Republican Party, nominee for MO-03 in 2010 and nominee for attorney general in 2012 Todd Richardson, Speaker of the Missouri House of Representatives Eric Schmitt, state treasurer Ann Wagner, U.S. representative and former U.S. Ambassador to Luxembourg David Wasinger, attorney
Endorsements
Debates + Hostnetwork Date Link(s) ParticipantsJoshHawleyAustinPetersenCourtlandSykesTonyMonettiPeterPfeiferKirstiNichols America First Missouri May 11, 2018 Absent Present Present Present Present Present
Polling Poll source Date(s)administered Samplesize Marginof error JoshHawley AustinPetersen CourtlandSykes Other UndecidedEmerson College April 26–29, 2018 283 ± 6.0% 37% 8% 6% 5% 45%
Poll source Date(s)administered Samplesize Marginof error JoshHawley DavidSteelman AnnWagner DavidWasinger UndecidedRemington Research Group April 28–29, 2017 915 ± 3.1% 30% 7% 14% 2% 47% 37% – 16% – 47%
Results
Libertarian primary Candidates Nominated Japheth Campbell, entrepreneur
Withdrew Don Donald Dennis Lagares
Declined Alicia Dearn, attorney and candidate for vice president of the United States in 2016 Austin Petersen, Libertarian candidate for president of the United States in 2016 (running as a Republican)
Results
Green primary Candidates Nominated Jo Crain
Eliminated in primary Jerome Bauer
Results
Independents Candidates Declared Craig O'Dear, attorney
General election
Predictions SourceRankingAs ofThe Cook Political Report October 26, 2018Inside Elections November 1, 2018Sabato's Crystal Ball November 5, 2018CNNNovember 5, 2018RealClearPoliticsNovember 5, 2018Daily KosNovember 5, 2018Fox NewsNovember 5, 2018FiveThirtyEightNovember 5, 2018
Debates Complete video of debate, October 18, 2018
Fundraising Campaign finance reports as of October 17, 2018 CandidateTotal receiptsTotal disbursementsCash on hand Claire McCaskill (D)$35,361,401$33,594,412$1,789,381 Josh Hawley (R)$10,221,143$7,376,209$2,844,933 Source: Federal Election Commission
Polling Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill(D) JoshHawley(R) JaphethCampbell(L) CraigO'Dear(I) JoCrain(G) Other UndecidedHarrisX November 3–5, 2018 600 ± 4.0% 45% 46% – – – – –HarrisX November 2–4, 2018 600 ± 4.0% 44% 47% – – – – –Trafalgar Group (R) October 29 – November 4, 2018 1,791 ± 2.3% 44% 48% – – – 4% 3%Emerson College November 1–3, 2018 732 ± 3.8% 46% 49% – – – 3% 3%HarrisX November 1–3, 2018 600 ± 4.0% 46% 46% – – – – –Missouri Scout/Remington (R) November 1–2, 2018 1,424 ± 2.6% 47% 47% 1% 1% 1% – 3%HarrisX October 31 – November 2, 2018 600 ± 4.0% 45% 46% – – – – –NBC News/Marist October 30 – November 1, 2018 600 LV ± 5.2% 47% 44% 3% – 2% <1% 4% 50% 47% – – – <1% 3% 920 RV ± 4.1% 46% 43% 3% – 2% 1% 6% 50% 46% – – – 1% 4%HarrisX October 30 – November 1, 2018 600 ± 4.0% 46% 43% – – – – –HarrisX October 29–31, 2018 600 ± 4.0% 45% 43% – – – – –HarrisX October 24–30, 2018 1,400 ± 2.6% 46% 44% – – – – –Fox News October 27–30, 2018 741 LV ± 3.5% 43% 43% 0% 3% 1% 0% 9% 45% 45% – – – 2% 8% 851 RV ± 3.0% 41% 42% 1% 3% 2% 1% 10% 43% 44% – – – 3% 9%Cygnal (R)Cygnal (R) October 26–27, 2018 501 ± 4.4% 46% 49% – – – 1% 3%Missouri Scout/Remington (R) October 24–25, 2018 1,376 ± 2.6% 45% 49% 1% 1% 1% – 3%Missouri Scout/Remington (R) October 17–18, 2018 1,215 ± 2.7% 46% 47% 2% 1% 1% – 2%OnMessage Inc. (R-Hawley) October 16–18, 2018 800 ± 3.5% 42% 49% – – – 4% 5%The Polling Company (R-Citizens United) October 11–13, 2018 600 ± 4.0% 47% 50% – – – 0% 3%Ipsos September 27 – October 7, 2018 1,111 ± 3.0% 44% 45% 1% 2% 0% 2% 6%1st Tuesday Campaigns October 5–6, 2018 1,052 ± 3.0% 42% 44% 1% 1% 1% – 11%Fox News September 29 – October 2, 2018 683 LV ± 3.5% 43% 43% 2% 4% 1% 1% 6% 46% 46% – – – 3% 5% 805 RV ± 3.5% 41% 41% 2% 4% 2% 1% 9% 44% 44% – – – 3% 8%McLaughlin (R-Missouri Rising Action) September 29 – October 2, 2018 600 ± 4.0% 44% 52% – – – – –Vox Populi Polling September 29 – October 1, 2018 869 ± 3.3% 49% 51% – – – – –CNN/SSRS September 25–29, 2018 756 LV ± 4.3% 47% 44% 3% – 1% 0% 4% 906 RV ± 3.9% 43% 42% 4% – 2% 0% 6%Missouri Scout/Remington (R) September 26–27, 2018 1,555 ± 2.5% 46% 48% – – – – 6%YouGov September 10–14, 2018 917 – 45% 45% – – – 4% 6%Trafalgar Group (R) September 11–13, 2018 1,724 ± 2.4% 44% 47% – – – – 8%Fox News September 8–11, 2018 675 LV ± 3.5% 44% 41% 1% 3% 1% 1% 8% 45% 45% – – – 3% 7% 808 RV ± 3.5% 41% 39% 1% 4% 1% 1% 11% 42% 43% – – – 3% 10%NBC News/Marist August 25–28, 2018 568 LV ± 4.8% 44% 40% 5% – 3% <1% 8% 47% 47% – – – 1% 5% 774 RV ± 4.2% 43% 39% 6% – 3% <1% 8% 46% 47% – – – 1% 5%WPA Intelligence (R-Club For Growth) August 12–14, 2018 501 ± 4.4% 41% 48% – – – 3% 8%Missouri Scout/Remington (R) August 8–9, 2018 1,785 ± 2.3% 47% 47% – – – – 6%WPA Intelligence (R-Club For Growth) July 10–12, 2018 602 ± 4.0% 42% 43% – – – 4% 11%The Missouri Times/Remington (R) July 7–8, 2018 1,034 ± 3.2% 46% 48% – – – – 6%SurveyMonkey/Axios June 11 – July 2, 2018 1,038 ± 5.0% 49% 47% – – – – 4%McLaughlin (R-Missouri Rising Action) June 2018 – – 46% 42% – – – – –Global Strategy Group (D-SMP) June 11–13, 2018 804 ± 3.5% 47% 41% – – – – –Gravis Marketing (R-Petersen) May 16, 2018 822 ± 3.4% 43% 50% – – – – 7%Missouri Scout/TJP Strategies (D) May 9–10, 2018 898 ± 3.3% 48% 44% – – – – 8%Emerson College April 26–29, 2018 600 ± 4.2% 45% 45% – – – – 11%Missouri Scout/TJP Strategies (D)Missouri Scout/TJP Strategies (D) April 19–20, 2018 1,542 ± 2.5% 48% 44% – – – – 8%OnMessage Inc. (R-Hawley) April 16–18, 2018 600 ± 4.0% 46% 47% – – – – 7%Global Strategy Group (D-SMP) April 9–12, 2018 – – 46% 44% – – – – –Mason-Dixon April 4–6, 2018 625 ± 4.0% 45% 44% – – – – 11%Gravis Marketing March 5–7, 2018 931 ± 3.2% 42% 40% – – – – 18%SurveyMonkey/Axios February 12 – March 5, 2018 1,938 ± 3.6% 44% 52% – – – – 4%Public Policy Polling (D-TMI) January 8–9, 2018 965 ± 3.2% 45% 44% – – – – 11%Missouri Scout/Remington (R) January 3–4, 2018 1,122 ± 2.9% 45% 49% – – – – 6%Missouri Scout/Remington (R) October 11–12, 2017 965 ± 3.1% 45% 48% – – – – 7%Missouri Scout/Remington (R)Missouri Scout/Remington (R) August 16–18, 2017 922 ± 3.0% 45% 50% – – – – 5%Fabrizio Lee (R) July 10–11, 2017 500 ± 4.4% 42% 46% – – – – 12%Missouri Scout/Remington (R) July 7–8, 2017 928 ± 3.2% 44% 50% – – – – 6%
with Austin Petersen Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) AustinPetersen (R) UndecidedGravis Marketing (R-Petersen) May 16, 2018 822 ± 3.4% 40% 56% 4%
with generic Republican Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) GenericRepublican UndecidedFabrizio Lee (R) July 10–11, 2017 500 ± 4.4% 38% 54% 8%
with Vicky Hartzler Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) VickyHartzler (R) UndecidedMissouri Scout/Remington (R) July 7–8, 2017 928 ± 3.2% 44% 48% 8%
with Blaine Luetkemeyer Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) BlaineLuetkemeyer (R) UndecidedMissouri Scout/Remington (R) July 7–8, 2017 928 ± 3.2% 43% 50% 7%
with Todd Richardson Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) ToddRichardson (R) UndecidedMissouri Scout/Remington (R) July 7–8, 2017 928 ± 3.2% 43% 48% 9%
with Eric Schmitt Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) EricSchmitt (R) UndecidedMissouri Scout/Remington (R) July 7–8, 2017 928 ± 3.2% 45% 49% 6%
with Jason Smith Poll source Date(s)administered Samplesize Marginof error ClaireMcCaskill (D) JasonSmith (R) UndecidedMissouri Scout/Remington (R) June 7–8, 2017 928 ± 3.2% 45% 48% 7%
Results
Senator McCaskill conceded a few hours after the polls closed on election day. Despite performing strongly in the St. Louis suburbs, she ran well behind her 2012 vote in Southeast Missouri, especially in the Lead Belt and the Missouri Bootheel. She also ran poorly in the northern part of the state.
Counties that flipped from Democratic to Republican Audrain (largest city: Mexico) Bates (largest city: Butler) Chariton (largest city: Salisbury) Clark (largest city: Kahoka) Clinton (largest city: Cameron) Daviess (largest city: Gallatin) Dunklin (largest city: Kennett) Franklin (largest city: Washington) Gentry (largest city: Albany) Grundy (largest city: Trenton) Henry (largest city: Clinton) Hickory (largest city: Hermitage) Howard (largest city: Fayette) Iron (largest city: Ironton) Knox (largest city: Edina) Lafayette (largest city: Odessa) Lewis (largest city: Canton) Linn (largest city: Brookfield) Livingston (largest city: Chillicothe) Madison (largest city: Fredericktown) Nodaway (largest city: Maryville) Pike (largest city: Bowling Green) Reynolds (largest city: Ellington) Schuyler (largest city: Lancaster) Scotland (largest city: Memphis) Scott (largest city: Sikeston) Shannon (largest city: Winona) St. Francois (largest city: Farmington) Sullivan (largest city: Milan) Wayne (largest city: Piedmont) Worth (largest city: Grant City) Buchanan (largest city: St. Joseph) Jefferson (largest city: Arnold) Mississippi (largest city: Charleston) New Madrid (largest city: New Madrid) Pemiscot (largest city: Caruthersville) Platte (largest city: Kansas City) Ray (largest city: Richmond)