Democrat Analilia Mejia has won the special election to fill New Jersey Gov. Mikie Sherrill’s seat in the U.S. House, NBC News projects, defeating Republican Joe Hathaway.

Mejia, a progressive activist backed by Sen. Bernie Sanders, I-Vt., and Rep. Alexandria Ocasio-Cortez, D-N.Y., entered Thursday’s contest in the 11th Congressional District as the favorite. Then-Vice President Kamala Harris won the district by 9 points in the 2024 presidential election, while Sherrill carried it by 15 points in her campaign for governor last year. And Mejia had outraised Hathaway, a Randolph Township Council member, by 2-to-1.

Mejia will fill the rest of Sherrill’s term and narrow Republicans’ House majority to 218-214.

She narrowly advanced from a crowded primary this year that featured veteran Democrats such as former Rep. Tom Malinowski, former Lt. Gov. Tahesha Way and Essex County Commissioner Brendan Gill.

While the 11th District had been represented by a more centrist Democrat in Sherrill, Mejia, a former Sanders staffer, ran on a progressive platform that included abolishing Immigration and Customs Enforcement, raising taxes on the wealthy and universal health care and child care. She has also been fiercely critical of President Donald Trump and of Israel, saying it has committed genocide in the Gaza Strip.

Mejia unintentionally benefited from United Democracy Project, the super PAC aligned with the American Israel Public Affairs Committee, attacking Malinowski in the February primary. She ended up winning that contest with less than 30% of the vote.

But given the Democratic lean of the district and the party’s success in special elections since Trump regained office last year, the general election in the 11th District was relatively quiet. Even on a Thursday, rather than the traditional Tuesday, Democratic voters appeared motivated to turn out for Mejia, continuing a trend seen in other lower-profile elections during the Trump era.

Mejia raised just more than $1 million by the end of March, according to the latest campaign finance reports, more than half of which came from contributions of less than $200. Hathaway raised $500,000 during that period.

And there wasn't much spending from outside groups. American Centerpoint, a super PAC that backs candidates who support Israel, tried to attack Mejia by tying her to New York Mayor Zohran Mamdani, a democratic socialist who was elected last fall, in the closing days of the race in a digital ad.

Hathaway, who ran opposed in the Republican primary, largely avoided talking about Trump on the campaign trail. He said at a debate this month that he would not be a “rubber stamp” for Trump, who did not endorse him.

There will be a regularly scheduled primary in June to serve a full term in the 11th District starting in 2027.