Anti-establishment candidates win big in Colorado primary elections

Anti-establishment momentum was clear in Colorado on Tuesday night, as primary election results rolling in indicate voters are leaning against the old guard. 

Voters generally favored more progressive-leaning candidates down the ballot, including in the 8th Congressional District, where state Rep. Manny Rutinel, who has drawn comparisons to New York City Mayor Zohran Mamdani, defeated former state Rep. Shannon Bird in the Democratic primary. That wasn’t the case everywhere, as evidenced in Colorado’s 5th Congressional District, where Army veteran Jessica Killin won her Democratic primary after signing onto a document affirming centrist principles and rebuking the socialist agenda. 

Socialists’ success caught the country’s attention in New York last week, when several candidates swept primaries. 

Their victories have spread to Colorado’s 1st Congressional District in Denver, where Rep. Diana DeGette (D-CO) suffered a resounding defeat to 29-year-old socialist Melat Kiros, backed by Sen. Bernie Sanders (I-VT). DeGette lost, 51.3% to 41.7%, despite being a 15-term incumbent and member of the Congressional Progressive Caucus.

Kiros is a left-wing candidate who has been accused of antisemitism. The former attorney was fired for writing a letter criticizing the idea that calling for Israel’s elimination was antisemitic. 

In another race for secretary of state, the candidate backed by the local chapter of the Democratic Socialists of America easily defeated state Sen. Jessie Danielson.

Amanda Gonzalez secured the victory, 63.5% to 36.5%, after serving as Jefferson County clerk and recorder since 2023. Gonzalez is also the former executive director of the voting rights group Colorado Common Cause.

Political observers initially viewed Sen. Michael Bennet (D-CO) as the favorite to win the Democratic nomination for governor. But voters firmly rejected him on Tuesday, handing Attorney General Phil Weiser the win, 55.7% to 44.3%. Bennet is now one of at least two incumbent U.S. senators who lost statewide primary races this year, signaling momentum against old guard candidates is gaining power.  

Weiser carried the primary election after leaning into socialist-styled rhetoric attacking billionaires, and branding himself as someone who will stonewall President Donald Trump, noting he has sued the administration over five dozen times. 

Voters also signaled distaste for the establishment on the Republican side in the gubernatorial primary. The race remains too close to call, but outsider Victor Marx has given state Sen. Barbara Kirkmeyer a run for her money. The results currently stand at 40.0% for Kirkmeyer and 39.6% for Marx. 

Marx’s gubernatorial bid marks his first run for public office. The feisty Marine veteran has framed Kirkmeyer as a failed politician, triggering a pledge from the state senator that she will not back her rival if he wins the nomination. 

Political strategists say young voters moving in large numbers to Colorado are boosting the progressive movement in the state. About half of all adults in metro Denver hold bachelor’s degrees or higher, according to census data released earlier this year, up from a 43.8% rate in 2019. Colorado has also seen the highest migration rate of millennials overall among the 50 states, with wealthy young people particularly attracted to the area, according to 2024 census data examined in a 2025 study. 

“You have a bunch of 20-something leftists absolutely clobbering well-funded moderates,” Democratic strategist Chris Nicholson told Axios. 

Democrats are hoping to flip at least two House seats in Colorado. The party needs to net just three seats to win back control of the House. 

In Colorado’s 8th Congressional District, Democratic voters on Tuesday selected Rutinel to challenge Rep. Gabe Evans (R-CO) in the fall. Evans is viewed as highly vulnerable, with the Cook Political Report rating the seat a toss-up. Trump won the area by less than a 2-point margin in 2024. Evans won the 2024 election by just 0.8%.

Rutinel defeated former state Rep. Shannon Bird in the primary. Bird was backed by the centrist Blue Dogs and other centrist Democratic groups. Republicans have compared Rutinel to Mamdani, New York’s first socialist mayor, with Evans campaign calling him a “far-left, radical socialist, Mamdani-wanna-be extremist.”  

During his campaign, Rutinel attacked Bird for a committee vote she took in 2025 that he argued failed to stand up to Immigration and Customs Enforcement officers. Though Rutinel previously supported socialist-style healthcare with Medicare for All and opposed fracking, he backed away from those positions on the campaign trail this year, as he’ll need to pull centrist voters in the district for the general election. 

Democrats also view Colorado’s 5th Congressional District as competitive this fall. On Tuesday, Democratic voters selected Killin to challenge Rep. Jeff Crank (R-CO) in November, as he wraps up his first term in Congress. The Cook Political Report shifted toward Democrats earlier this year, from “solidly” to “likely Republican.”  

Killin was former second gentleman Doug Emhoff’s chief of staff. She has stuck to a centrist agenda in the race, bucking the growing socialist trend in the party by recently signing onto the “Promise to America” set of centrist principles. 

Advocates believe she has a chance of becoming the first-ever Democrat to represent the 5th Congressional District, as it has moved leftward over the past few cycles. Trump won El Paso County in 2024 by 10 points, down from 11 points in 2020. Gov. Jared Polis (D-CO) lost his first gubernatorial campaign in El Paso County by 17 percentage points. In 2022, he lost it by just 4 points.