Democrats embrace insurgent candidates as primary upsets unsettle establishment

Progressive Democrats toppled two House incumbents in New York on June 23 and then scored another major upset in Colorado on June 30, intensifying a fight inside the party over whether anti-establishment candidates can carry Democrats to victory in November.

In New York, candidates backed by Zohran Mamdani defeated two incumbent House Democrats in the party’s congressional primaries. A week later in Colorado, Melat Kiros ousted Rep. Diana DeGette in a Denver-area seat DeGette had held for 29 years. The back-to-back defeats underscored how quickly Democratic primary voters have shifted toward candidates who cast themselves as challengers to Washington, party leaders and corporate money.

The pattern is showing up across the 2026 midterm calendar, where primary contests began in early March and continue through the summer before the November general election. Control of both chambers of Congress is on the line, and that gives the intra-party debate extra weight. Democratic strategists say candidates are increasingly presenting themselves as fighters against a system they say is “broken,” while also harnessing anger at Donald Trump.

That appetite for insurgents is forcing even establishment Democrats to adjust. Candidates with closer ties to Washington are moving to distance themselves from the capital, stress local issues and avoid looking too attached to party powerbrokers such as Hakeem Jeffries and Chuck Schumer. Roy Cooper, Morgan Jackson, Alec Hernandez, Erin Doherty, Andrew Howard, Will Steakin, Ali Bianco and Lisa Kashinsky are among the names circulating in the broader coverage of the party’s changing posture, as Democrats try to redefine what makes a nominee viable.

The gains have energized left-leaning activists, but they have also deepened anxiety among Democrats who fear the price of a crowded, costly primary season. Party lawmakers and strategists worry that hard-fought nomination battles could leave nominees short on money and bruised before facing Republicans in swing districts in November. For Democrats trying to retake the House, the question is no longer whether the insurgent wing can win primaries. It is whether the party can absorb the upheaval without weakening itself where the general election will be decided.