Rep. Diana DeGette has held her Denver seat since Bill Clinton was president. On Tuesday, she could lose it to Melat Kiros, a democratic socialist backed by the party’s insurgent left. Earlier this year, few national observers appeared to be taking the race seriously. Now, millions of dollars flowing in during the closing weeks have raised the stakes.

Heading into Tuesday’s primary, outside groups have poured around $3 million into the race over its final weeks, federal campaign finance records show — most of it to help DeGette, an incumbent of nearly three decades, fend off a challenger decades young and backed by the Democratic Socialists of America.

A Kiros victory would likely deliver an even more damning rebuke to the party establishment than New York City voters did last week. There, Mayor Zohran Mamdani put his substantial political sway towards helping his fellow DSA-backed candidates, giving them a powerful, popular and persuasive local ally against what was regarded as the establishment. 

In Colorado, that’s just not the case. Progressive Sen. Bernie Sanders, I-Vt., has endorsed Kiros, giving her legitimacy on the left. But in this race, Kiros does not have a Mamdani. Yet she does have an argument against an incumbent who has held the seat since 1997, in a blue city in a blue state that could come to host the next Democratic National Convention in two years’ time. 

“What voters are realizing now is that those that are running as democratic socialists are the ones that are committed to the values that working families care about,” Kiros said. 

The largest outside spending group in the primary contest, Pro-Choice Majority Action, invested around $1.5 million in defeating Kiros, and has financial ties back to the American Israel Public Affairs Committee. Most of its disclosed funding so far has come from the group EDW Action Fund, which has been bolstered with $750,000 by a major political group associated with AIPAC in May alone. 

“It’s a close race, and we’ll see what happens. Ultimately, it’ll be in the hands of the people of Denver,” House Democratic Leader Hakeem Jeffries said to reporters on Monday, adding that DeGette “has had an extraordinary career in the United States House of Representatives, and she’s forcefully making her case.” 

Kiros, who is also being helped by the insurgent Justice Democrats organization, hasn’t been shy about where she stands on issues involving Israel. And those stances have become a fixture in the contest in its final days. 

A month after the deadly attack on Israel led by Hamas in October 2023, which killed around 1,200 people, Kiros wrote in a blog post that “the Israeli government has weaponized anti-Semitism to defend its crimes against the Palestinian people and quell any resistance or critique against it.” 

In reference to a video of Sen. Kirsten Gillibrand, D-N.Y., who leads the Senate Democrats’ campaign arm, Kiros wrote in a September 2025 social media post “They’re so afraid of upsetting AIPAC that they’re letting Israel commit genocide against the Palestinians by bombing them and starving them, all with our tax dollars. We cannot wait for them to find the courage to stand for what’s right, it’s time to clean house on all of them.” 

That kind of intraparty scorn wouldn’t typically help someone who wants to become a Democrat in Congress. But ripping on Democrats seen as not doing enough to fight, or being too eager to compromise with Republicans, has become one way for a challenger to stand out. 

DeGette, who first won her seat when Bill Clinton was president, has stressed her own progressive credentials. A part of her campaign website with messaging advice for “allies” casts her as “fighting Donald Trump to protect our democracy,” and argues “Kiros is pushing an extreme agenda,” given her DSA support. 

That DeGette appears to be at risk speaks to the odd moment the Democratic Party is facing. Longtime incumbents like her, who have banked on seniority and the strength of incumbency, have of course been challenged over the years and sometimes lost. 

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But such upsets have been relatively difficult, given the stark difference in resources an incumbent can usually marshal again to be able to deploy against a little-known challenger. Yet now, firmly in President Donald Trump’s second term, Democratic voters are showing a willingness to consider other paths. 

“Melat is a superstar candidate who has excited a lot of people around the country, and she has an excellent chance of prevailing,” said Rep. Ro Khanna, a California progressive. “She’s running with a moral clarity on Gaza, she’s running with a sense of standing up to billionaires and trillionaires, and she’s exciting a new generation of voters.” 

DeGette, a member of the Congressional Progressive Caucus, is hardly a centrist. But the campaign she faces reflects the deeper existential dilemmas Democrats are grappling with — dilemmas facing the party across the nation.

What is clear is that there’s a growing window and opportunity for voters in urban areas to toss aside the Democrats they have come to know. By doing that, they may bring in a coalition that tears away at the candidates towards the center that give the party a chance to even be in power in the first place. 

“There’s a new group of democratic socialists who are socialists, who are not common-sense Democrats, who are not interested in getting things done,” Rep. Josh Gottheimer, a moderate Democrat from New Jersey, told reporters in the aftermath of New York City’s results. “They’re interested in throwing bombs, not actually solving problems.”

Kiros could also be another unpredictable element for party leaders if Democrats retake the House. 

On the night of last November’s off-year elections, Jeffries, the House Democratic Leader who is in line to be the party’s next speaker of the House, said on social media that “Democrats are smoking Donald Trump and Republican extremists throughout the country. Enough with the premature obituaries.The Democratic Party is back.” 

Kiros responded to Jeffries succinctly: “with virtually no help from you.” 

Kevin Frey contributed reporting to this article.

Hunter Woodall

Hunter Woodall covers politics for MS NOW. He’s reported on politics and presidential campaigns for The Associated Press and CBS News and reported on Congress for The Minnesota Star Tribune.