The anti-establishment wave surging through the Democratic Party reached Colorado on Tuesday, when democratic socialist Melat Kiros dislodged 15-term Rep. Diana DeGette, and state Attorney General Phil Weiser thwarted Sen. Michael Bennet’s quest to become governor.

In the Denver-anchored 1st District, Kiros, a lawyer and doctoral student, was leading DeGette, 51 percent to 42 percent just after midnight Wednesday, when The Associated Press called the race. University of Colorado Regent Wanda James trailed with 7 percent.

Kiros’ win marks another victory for the progressive group Justice Democrats and the Democratic Socialists of America, which backed two candidates who ousted a pair of House members from New York last week. 

Colorado was also the latest testing ground for many of the themes roiling Democratic politics this year, including debates over age and the advantages of incumbency, whether the U.S. should curtail or end military support for Israel, and questions of how aggressively the party ought to push back against President Donald Trump’s agenda.

“Denver voters of all ages, of all races, of all religions sent a clear message: We will not wait,’’ Kiros told supporters in Denver after she was declared the winner. “We will not wait to take the fight to Donald Trump and the oligarchy, we will not wait to abolish ICE and pass ‘Medicare for All.’ … And no, we will not wait to end the genocide in Palestine.”

The success of the Democratic Party’s left flank has also fueled attacks by Trump and congressional Republicans against what they say is a communist threat.

In the battleground 8th District, state Rep. Manny Rutinel, who campaigned on a populist message and was boosted by spending by the campaign arm of the Congressional Hispanic Caucus, won the Democratic nomination to take on vulnerable Republican freshman Gabe Evans in a contest that could determine which party controls the House. 

Rutinel decisively defeated former state Rep. Shannon Bird, who was backed by the centrist Blue Dog PAC. Rutinel was leading Bird 61 to 34 percent early Wednesday with 88 percent of the vote in, according to the AP. Evans was unopposed for the Republican nomination.  

Bennet’s defeat was a stunning reversal of fortune for Colorado’s senior senator and former presidential candidate, who held a 31-point lead over Weiser a year ago. With about 85 percent of votes in, Weiser was leading the senator 55 percent to 45 percent, the AP reported. Despite his defeat, Bennet will remain in the Senate, where he is not up for reelection until 2028. 

One notable Colorado Democrat survived a primary challenge from his left flank. Sen. John Hickenlooper, a pillar of the state’s political establishment and a former governor and Denver mayor, defeated state Sen. Julie Gonzales, who ran on a progressive platform.

Hickenlooper, who was leading his opponent by around 11 points early Wednesday, has pledged that his current run will be his last Senate race. He will next face Republican state Sen. Mark Baisley. 

A stunning upset

Kiros, who was born in Ethiopia and grew up in the Denver area, launched her challenge to DeGette last July. At the time, she was viewed as a long shot, but her campaign for the deep-blue seat gained momentum over the following year, culminating in a surprising first-place finish at a district party assembly in March. The result was an early warning sign for DeGette, who took 33 percent of the assembly vote, barely qualifying for the primary ballot. 

Kiros, who is poised to become the first Gen Z woman in Congress, made her opposition to the war in Gaza a central focus of her campaign. She moved home to Colorado after being fired from her New York law firm over her refusal to take down a Medium post in which she argued against conflating calls for the “elimination of the Israeli state” with antisemitism. 

First elected in 1996, before Kiros was born, DeGette has been a reliable progressive in Congress. She’s the top Democrat on the Energy and Commerce Health Subcommittee and made her seniority a key part of her closing argument to voters. 

She had the backing of her fellow Democrats in the Colorado delegation, as well as the Congressional Progressive Caucus. As she sought reelection, she touted her efforts to lower the cost of insulin, protect access to reproductive health and stressed her progressive bona fides, including being a co-sponsor of legislation that would establish “Medicare for All.” 

But Kiros, who was endorsed by Vermont Sen. Bernie Sanders and left-wing streamer Hasan Piker, cast herself as a political outsider who would shake up the system, while painting DeGette as part of an ineffectual old guard propped up by billionaires and corporations. 

Battleground matchup

Ideological rifts also marked the Democratic primary in the 8th District, north of Denver. Bird pitched herself as a centrist who could win over the district’s swing voters, while Rutinel leaned into his working-class roots. He also highlighted his heritage as the son of an immigrant from the Dominican Republic, which boosted his profile in a district where Latinos make up about 40 percent of the adult population.

“Tonight has shown that the son of a single mom who grew up working at McDonald’s and filling out food stamp and Medicaid forms can go on to become an economist in the US Army Corps of Engineers, serve in the Colorado legislature, and now become the nominee for Congress in the most competitive seat in the country,’’ Rutinel said in a statement.

Rutinel outraised Bird and was also the primary beneficiary of outside spending in the race. Republicans – and some Democrats – have argued that he is too liberal for the purple district, which Trump carried by 2 points in 2024. Rutinel, though, has recently shied away from some of his more progressive views, including a ban on fracking and the cancellation of all student debt. 

A spokesman for the National Republican Congressional Committee cast the wins by Rutinel and Kiros as a sign that socialists were dominating the Democratic Party. 

“The radicals are taking over battleground districts, putting must-win seats out of reach for Democrats and sinking their chances of flipping the House,’’ NRCC national press secretary Mike Marinella said in a statement.

Inside Elections with Nathan L. Gonzales rates the 8th District race a Toss-up. 

Other races

In the gubernatorial contest, Bennet significantly outraised Weiser in addition to benefiting from a flurry of outside spending.

But as Trump loomed over the race, Weiser highlighted the more than 64 lawsuits he’s filed against the administration and also criticized Bennet for voting to confirm several of Trump’s Cabinet nominees.  

Weiser enters the general election as the favorite in a deep-blue state that last elected a Republican governor in 2002. The GOP gubernatorial race remained uncalled early Wednesday, with state Sen. Barb Kirkmeyer narrowly ahead of pastor and Marine veteran Victor Marx. 

Meanwhile, the fall matchups are set in two other competitive Republican-held House seats.

In the 5th District, Army veteran Jessica Killin won the Democratic nomination to take on Republican freshman Jeff Crank. The Democratic Congressional Campaign Committee has added Killin to its “Red to Blue” program, a signal that it sees the Colorado Springs-based seat as flippable in November.

And in the 3rd District, which includes the state’s Western Slope, GOP freshman Jeff Hurd, who briefly lost Trump’s support for reelection, fended off former state Rep. Ron Hanks in a primary rematch. He will next face Democrat Dwayne Romero, an Army veteran and former Aspen City Council member. 

Inside Elections rates both House races Likely Republican.