An election was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Colorado, concurrently with the 2020 U.S. presidential election, as well as other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections.
Under Colorado law, the filing deadline for U.S. Senate candidates was March 17, 2020, the third Tuesday in March of the election year; the primary election occurred on June 30. Incumbent Senator Cory Gardner lost re-election to former Governor John Hickenlooper. Gardner was unopposed in the Republican primary, and Hickenlooper defeated former State House Speaker Andrew Romanoff in the Democratic primary.
This race was one of two Republican-held U.S. Senate seats up for election in 2020 in a state President Trump lost in 2016; the other was in Maine. Many pollsters and pundits considered Gardner to be the most vulnerable Republican senator facing re-election in 2020 due to his narrow victory in 2014, the state's leftward shift, and Trump's unpopularity in the state.
As predicted, Hickenlooper easily defeated Gardner by a 9.3-point margin. However, Gardner did manage to outperform Donald Trump in the concurrent presidential election by roughly four points. This became the first election Gardner had lost in his political career as well as being the widest margin of loss for a Coloradan U.S. Senator since 1978. This was the third consecutive election in which this seat flipped parties.
At 68, Hickenlooper was the oldest elected freshman U.S. senator from Colorado.
Background Gardner was elected to the U.S. Senate in 2014, narrowly defeating incumbent Democratic senator Mark Udall in a very successful election year for Republicans. Gardner was widely considered vulnerable in 2020 due to Colorado's recent Democratic trend and his support for Trump. Polling showed that more voters had a negative view of Gardner compared to a positive one. Gardner also faced a four-year grassroots campaign across the state by progressive political activists to hold him accountable for his votes, featured a cardboard cutout dubbed "Cardboard Cory". The seat was expected to be highly competitive and the most likely Republican-held seat to flip Democratic. The Democratic nominee, former governor John Hickenlooper, had a consistent double-digit lead over Gardner in the polls.
Various minor scandals in the days leading up to the June 30 Democratic primary sparked speculation that Romanoff might win, but Hickenlooper had an advantage in name recognition, and harsh negative attacks by Romanoff reportedly led many state Democrats and voters to sour on him.
Republican primary Candidates Nominee Cory Gardner, incumbent U.S. senator
Withdrawn Margot Dupre, estate agent Gail Prentice, veteran and business owner
Endorsements
Results
Democratic primary Candidates Nominee John Hickenlooper, former governor of Colorado and former candidate for president of the United States in 2020
Eliminated in primary Andrew Romanoff, former Speaker of the Colorado House of Representatives, candidate for U.S. Senate in 2010, and nominee for Colorado's 6th congressional district in 2014
Withdrawn Dan Baer, former executive director of the Colorado Department of Higher Education and former United States Ambassador to the Organization for Security and Cooperation in Europe (endorsed John Hickenlooper) Derrick Blanton Marcos Boyington, software engineer Diana Bray, psychologist and climate activist (endorsed Andrew Romanoff) Denise Burgess, businesswoman and Denver Metro Chamber of Commerce board member Ellen Burnes, Colorado State University professor and former chair of the Boulder County Democratic Party Lorena Garcia, community organizer David Goldfischer, associate professor at the Korbel School for International Studies at the University of Denver and national security advisor Mike Johnston, former state senator and candidate for Governor of Colorado in 2018 Danielle Kombo, medical recruiter and businesswoman (endorsed Stephany Rose Spaulding) Dustin Leitzel, pharmacist Alice Madden, former majority leader of the Colorado House of Representatives Christopher Hawkins Critter Milton, 2020 Unity Party nominee for Colorado's 3rd congressional district Keith Pottratz, technician and veteran (endorsed Lorena Garcia) Stephany Rose Spaulding, professor at University of Colorado Colorado Springs and nominee for Colorado's 5th congressional district in 2018 (endorsed Lorena Garcia) Erik Underwood, entrepreneur and candidate for Governor of Colorado in 2018 John F. Walsh, former U.S. Attorney for the District of Colorado (endorsed John Hickenlooper) Michelle Ferrigno Warren, nonprofit leader, immigration advocate Angela Williams, state senator (ran for re-election) Trish Zornio, biomedical scientist (endorsed John Hickenlooper)
Declined Diana DeGette, incumbent U.S. representative (ran for re-election) Kerry Donovan, state senator (endorsed John Hickenlooper) Crisanta Duran, former speaker of the Colorado House of Representatives (ran for Colorado's 1st congressional district, then withdrew) Jena Griswold, Colorado Secretary of State Cary Kennedy, former Colorado State Treasurer Joe Neguse, incumbent U.S. representative for Colorado's 2nd congressional district (ran for re-election) Ed Perlmutter, incumbent U.S. representative for Colorado's 7th congressional district (endorsed John Hickenlooper) Joe Salazar, former state representative
Endorsements
Polling Poll source Date(s)administered Samplesize Marginof error JenaGriswold JohnHickenlooper MikeJohnston AndrewRomanoff Other /UndecidedSurveyUSASurveyUSAJune 19–24, 2020575 (LV)± 6.0% –58% –28%15%Myers Research and Strategic ServicesMyers Research and Strategic ServicesJune 16–17, 2020500 (LV)± 4.4% –51% –39% –Unspecified polling firmUnspecified polling firmOctober 2019 – (LV) – –68% – 19% – September 3, 2019 Johnston withdraws from the racePublic Policy Polling (D)Public Policy Polling (D)August 28–29, 2019509 (LV) – – 60% 3% 9% 27% –66% –17%17% August 21, 2019 Hickenlooper announces his candidacy August 9, 2019 Griswold announces that she will not runGarin-Hart-Yang Research GroupGarin-Hart-Yang Research Group July 25–28, 2019 600 (LV) – 6% 61% 10% 8% 15%Public Policy Polling (D)Public Policy Polling (D) July 12–14, 2019 561 (LV) – 4% 44% 3% 12% 38%
with Dan Baer and John Hickenlooper Poll source Date(s)administered Samplesize Marginof error DanBaer JohnHickenlooper UndecidedPublic Policy Polling (D) August 28–29, 2019 509 (LV) –11%72%17%
with John Hickenlooper and Mike Johnston Poll source Date(s)administered Samplesize Marginof error JohnHickenlooper MikeJohnston UndecidedPublic Policy Polling (D) August 28–29, 2019 509 (LV) –69%14%18%
with John Hickenlooper and Alice Madden Poll source Date(s)administered Samplesize Marginof error JohnHickenlooper AliceMadden UndecidedPublic Policy Polling (D) August 28–29, 2019 509 (LV) –69%14%17%
with John Hickenlooper and Angela Williams Poll source Date(s)administered Samplesize Marginof error JohnHickenlooper AngelaWilliams UndecidedPublic Policy Polling (D) August 28–29, 2019 509 (LV) –70%11%18%
Caucus On March 7, 2020, the Colorado Democratic Party held a non-binding Senate primary preference poll at its caucus sites. Attendees could choose delegates to county and then state conventions. If a candidate received at least 30% of the delegates at the state convention they would be placed on the ballot. Some candidates were not listed because they instead chose to attempt to collect signatures to reach the ballot. Candidates needed 1,500 signatures from each congressional district. Hickenlooper and Underwood chose to do both. Romanoff collected the needed signatures as of March 8, 2020.
Caucus results Romanoff was the only candidate to get more than 30% in the initial precinct caucuses. Hickenlooper withdrew from the assembly process soon afterward, choosing to qualify for the ballot exclusively by petition. Ballot access for assembly candidates will be decided at the state assembly. Caucus winners do not always receive the party's nomination; Romanoff won them in the 2010 Democratic primary for Colorado's Senate race, but Michael Bennet won the party's nomination that year.
The aggregate results of the various precinct caucuses on March 7, 2020, were:
Candidate Total raw votes Percentage of vote won (%) Andrew Romanoff8,62954.98John Hickenlooper4,76130.34 Trish Zornio9766.21Stephany Rose Spaulding7714.91 Uncommitted5203.31 Erik Underwood350.22
Results
Other candidates Libertarian primary Nominee Raymon Doane, Libertarian nominee for Colorado's 1st congressional district in 2018
Eliminated in primary Gaylon Kent, author and perennial candidate
Results
Unity Party Nominee Stephan "Chairman Seku" Evans, former candidate for mayor of Denver
Eliminated at Unity Party convention Joshua Rodriguez
Withdrawn Gary Swing, perennial candidate
Write-in candidates Declared Dan Doyle (Approval Voting Party) Bruce Lohmiller (Green Party) Theodore Rockwell, Steamboat Springs (independent) Michael Sanchez (independent) Danny Skelly, small business owner (independent)
Withdrawn Veronique Bellamy, former candidate for RTD board (Socialist Party) Joseph "Joey" Camp, performance artist (independent) Lisa Garcia (independent) Christopher K. Springer (independent) Donald George Willoughby (independent) Marti Wolf (independent)
General election Debate HostDate & timeLink(s)ParticipantsJohn HickenlooperCory GardnerColorado State UniversityOctober 13, 20206:00pm MDTLink
Predictions SourceRankingAs of The Cook Political Report October 29, 2020 Inside Elections October 28, 2020 Sabato's Crystal Ball November 2, 2020Daily Kos October 30, 2020PoliticoNovember 2, 2020RCPOctober 23, 2020DDHQNovember 3, 2020538November 2, 2020EconomistNovember 2, 2020
Post-primary endorsements
Polling Graphical Summary
Poll results