Rep. Alexandria Ocasio-Cortez’s (D-NY) loss to a senior colleague for a plum committee leadership position has progressives fuming, highlighting the deepening divide between factions of the Democratic Party.

After assuming office nearly six years ago, the 35-year-old New Yorker recently mounted a bid to become the top Democrat on the influential House Oversight Committee. As a young progressive, Ocasio-Cortez’s move challenged Rep. Gerry Connolly (D-VA), 74, an establishment candidate backed by old-guard Democrats.