Democratic socialist Melat Kiros defeated 15-term Colorado Rep. Diana DeGette on Tuesday, delivering one of the biggest shocks of the Democratic primary season amid a growing streak of wins for the insurgent left.
Kiros’ win in the contest for Colorado’s 1st District topples a 68-year-old representative who had held the seat since before her 29-year-old challenger was born.
It’s a victory that echoes Rep. Alexandria Ocasio-Cortez’s (D-N.Y.) stunning 2018 upset over 10-term incumbent Joe Crowley in New York, and delivers democratic socialists fresh momentum.
DeGette’s loss, after representing the district since 1997, seemed unthinkable in the state just months ago, but Kiros rode the same anti-incumbent wave that swept through New York’s Democratic primaries last week, where Reps. Adriano Espaillat and Dan Goldman were ousted in a dramatic show of the left’s growing strength.
The defeat is a stunning one for the Democratic establishment, though warning signs had been building for months inside DeGette’s campaign, with allies privately acknowledging the race was tightening and the representative’s team spending weeks urging national Democrats and allied groups to come to her aid.
Kiros launched her campaign nearly a year ago, framing it from the outset as a generational reckoning with the Democratic establishment. She cast DeGette, a longtime progressive who served as an impeachment manager against President Donald Trump, as a corporate-backed incumbent who was out of step with her constituents, and called for a new era of progressive leadership in Congress.
Kiros’ campaign drew major outside support from progressive leaders, including endorsements from Sen. Bernie Sanders and the Working Families Party, as well as backing from the candidates who upended New York’s Democratic delegation last week.
Her win marks the seventh primary victory this cycle for Justice Democrats, the progressive group that recruited and backed her, making 2026 the organization’s most successful primary year to date.
“We are so proud to be sending Colorado’s first Justice Democrat to Congress,” said Alexandra Rojas, executive director of Justice Democrats. “Melat built a movement that inspired Denverites to remember they themselves have the power to transform what kind of Democratic Party they want to be represented by. Melat and our candidates continue winning this cycle because Democratic voters are finally getting leaders acting on their demands.”
Down the final stretch of the campaign, DeGette’s allies scrambled to hold off Kiros’ rise, with outside groups pouring roughly $2.3 million into the race over the final month, including $1.3 million in the race’s final days. DeGette’s side held a nearly three-to-one spending advantage down the stretch.
DeGette also secured last-minute endorsement videos from Rep. Pramila Jayapal (D-Wash.), a former chair of the Congressional Progressive Caucus, and progressive Rep. Jamie Raskin (D-Md.), who like DeGette was a manager of Trump’s impeachments. Still, that wasn’t enough to help her keep her seat.
The new class of hard-left members of Congress could prove a tough group to wrangle for House Minority Leader Hakeem Jeffries (D-N.Y.), particularly if Democrats win a narrow majority in the House this fall.
“If the day comes to vote and he continues taking corporate PAC money, I won’t be voting for him,” Kiros said in an interview prior to Tuesday’s win.