Alexandria Ocasio-Cortez, a 28-year-old, Bernie-Sanders-supporting political novice, has defeated incumbent Rep. Joe Crowley (D-NY) in the 14th congressional district in the New York primary.

With 88% of precincts reporting in the heavily-Democratic district that spans Queens and the Bronx, Ocasio-Cortez had crushed Crowley, 57.6% to 42.4%, a margin of nearly 3,600 votes.

CNN notes that Ocasio-Cortez is a self-described “democratic socialist.”

Crowley, currently in his 10th term and the chair of the House Democratic Caucus — ranked 4th in the whole caucus — was considered a possible future candidate for Speaker of the House, and had not faced a primary challenge in 14 years.

He has now become the first major casualty of the so-called “Resistance” — the left-wing movement that emerged to oppose President Donald Trump but has also clashed with the Democratic Party establishment.

Left: a campaign poster for Ocasio-Cortez. Right: Ocasio-Cortez celebrates with supporters at a victory party in the Bronx. (Scott Heins/Getty Images)

Politico observes that Ocasio-Cortez “challenged Crowley on ideological and racial grounds.” She argued that the district needed a more left-wing representative, as well as someone who reflected the “majority-minority” demographic of the area, which has become increasingly Latino. (Or, as she prefers, “Latinx.”)

Ocasio-Cortez ran on an explicit promise to abolish the federal Immigrations and Customs Enforcement (ICE) agency, as well as to nationalize health care.

In the last days before the primary, Ocasio-Cortez traveled to McAllen, Texas to join left-wing protests against President Trump’s immigration policies. She organized a large volunteer contingent to canvass her district while she was away.

Ocasio-Cortez also appears to hold anti-Israel views, calling Israel’s response to violent Hamas “protests” at the Gaza border a “massacre.”

She also attacked Crowley for his alleged support for the transfer of the U.S. embassy in Israel from Tel Aviv to Jerusalem.

Ocasio-Cortez enjoyed the support of left-wing celebrities like Susan Sarandon, who hails from the area. Her campaign ads were sharp, innovative, and eye-catching. And she drew on widespread grassroots frustration with the Democratic Party establishment.

The left may have found a new standard-bearer — and Republicans may have found a new target.

President Trump celebrated her win over one of his loudest critics:

Trump also framed her win in terms of the overall 2018 contest:

Ocasio-Cortez will face Republican Anthony Pappas, an economics professor, in November.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.