Twenty-nine-year-old Democratic socialist Melat Kiros defeated 15-term Democratic incumbent Rep. Diana DeGette in Colorado's Democratic congressional primary, ending one of the longest-serving House careers in the state. The stunning victory has sparked intense debate about the future of the Democratic Party, with some House Democrats reportedly describing the result as a 'wake-up call' for the party establishment.

A House race in the blue stronghold of Denver has quickly become the next test of Democrats’ appetite for socialism.

Colorado's primary has Democratic incumbents fighting off challenges ranging from progressive newcomers to state lawmakers seeking higher office.