Melat Kiros, a 29-year-old democratic socialist and first-time candidate, defeated 15-term incumbent Rep. Diana DeGette on Tuesday in Colorado's 1st Congressional District primary, the latest signal that progressive momentum and backlash against the Democratic establishment are spreading nationwide."We won tonight, but this is also something so much bigger than this moment," Kiros, who was fired from the law firm Sidley Austin in 2023 for speaking out in support of Palestinian rights demonstrators, told backers late Tuesday after The Associated Press called the race in her favor. "We believe that fundamental change can, and will, happen if we fight for it—if we organize, if we show no fear in standing up for what’s right. That is the message that Denver has sent to both parties, to Donald Trump, and to the entire country."Kiros' upset win came a week after a series of progressive victories in New York congressional primaries, which sparked backlash from the party's corporate wing. Days after the New York contests, more than a dozen centrist Democrats signed an open letter declaring that "we are capitalist, not socialist," a clear rebuke of insurgent progressives.Justice Democrats, a national progressive group that backed Kiros, said it is having its "most successful cycle to date, winning six Democratic primaries and proceeding to the top two in two California primaries." The organization recruited Darializa Avila Chevalier, who upset five-term incumbent Rep. Adriano Espaillat in New York's 13th Congressional District last week."Melat and our candidates continue winning this cycle because Democratic voters are finally getting leaders acting on their demands to bring the fight to the corporations raising our prices, the war lobbies profiting off endless war and genocide, and the immigration gestapo terrorizing our communities," Alexandra Rojas, Justice Democrats' executive director, said in a statement Tuesday.Kiros—whose platform includes Medicare for All, universal childcare, and abolishing Immigration and Customs Enforcement—prevailed despite a last-minute torrent of super PAC spending in support of DeGette. Drop Site reported that "super PACs funded by AIPAC and major big tech donors have poured roughly $2 million behind Rep. Diana DeGette on the eve of her contentious primary.""Across the country, voters are rejecting corporate politics and electing candidates willing to take on billionaire influence, confront the climate crisis, fight for working people, and speak with moral clarity on the defining issues of the moment," said the youth-led Sunrise Movement following Kiros' win.Kiros will be the heavy favorite to win the general election in November, when she will face Republican Christy Peterson.Progressives also celebrated Colorado Attorney General Phil Weiser's Democratic gubernatorial primary win over US Sen. Michael Bennet, whose campaign received nearly $3 million in support from billionaire former New York City Mayor Michael Bloomberg.“This movement is what democracy looks like,” Weiser told supporters late Tuesday. “You all sent a very clear message: The future of Colorado will not be decided by out-of-state billionaires, by corporations or special interests. Colorado’s future belongs to all of us."