The fourth-ranking Democrat in the US House has lost his bid for another term in a New York primary.
Alexandria Ocasio-Cortez, a 28-year-old activist who ran on abolishing ICE and making Medicare a universal programme, defeated Congressman Joe Crowley in an upset.
Crowley is the first incumbent Democrat to lose renomination since 2014, when a Massachusetts Democrat was brought down by scandal.
Crowley, who was first elected in 1998, had grown his profile inside the party and faced no personal controversies.
But Ocasio-Cortez argued that the increasingly non-white district, which stretches from the Bronx to Queens, had been represented too long by a figure from the local political machine.
Crowley, who chaired the Queens Democratic Party while serving in Congress, had played a major role in determining candidates for local offices.
Ocasio-Cortez said that Crowley had grown too distant — he enrolled his children in a Northern Virginia school — and too dependent on donations from corporate PACs.
Crowley took the challenge seriously, spending US$1.5 million in his first primary since 2004.
He was the first member of Democratic leadership to endorse the House's universal Medicare bill, and he joined protests against the Trump Administration's travel ban and its immigration control policies.
Ocasio-Cortez told voters that they could do better — she refused corporate PAC money, emphasising that most of the US$300,709 she'd raised for the campaign came from small donors, most of them from in and around the district.