The progressive group that helped put Alexandria Ocasio-Cortez in Congress is turning its sights on the congressional district next door, backing a middle school principal in a Democratic primary challenge against Rep. Eliot Engel.

The Bronx-based district is the next battleground in the simmering civil war between the insurgent-left and the party's establishment, including the Democratic Congressional Campaign Committee, which has vowed to back all incumbents.

Justice Democrats and allied groups are focusing this year on targeting moderate Democrats in safe blue districts, rather than emphasizing trying to win swing seats. Last week, the group announced it was also supporting a primary challenger to Rep. Henry Cuellar, D-Texas.

Jamaal Bowman launched his campaign in New York's 16th congressional district with a spirited launch video discussing his family, professional background, and his case for taking on his opponent: 30-year incumbent Eliot Engel. Jamaal Bowman for Congress / via YouTube

Jamaal Bowman, a former New York City public school teacher and activist, is launching his campaign Tuesday with the endorsement of Justice Democrats, the group that recruited Ocasio-Cortez last year to take on Joe Crowley, the district's longtime Democratic representative.

"Our grassroots movement shocked the country last year with AOC's upset victory, and we are prepared to do it again in New York’s 16th District," said Alexandra Rojas, executive director of Justice Democrats. "It's time to usher in a new generation of progressive leadership into the Democratic Party."

Engel has represented a safe Democratic seat in Congress for 30 years and faced primary challenges before, including in last year's midterms. He won that race in a landslide, before cruising to re-election unopposed.

But that was before Ocasio-Cortez's rise. And his tenure has given Engel a long record of votes that Bowman plans to highlight.

"Over those 30 years, my opponent voted for an unjust war in Iraq, deregulating Wall Street, school privatization and building more prisons. While the very few at the top continue to build their wealth and power, the majority of us continue to struggle," Bowman says in his launch video.

Engel's district, which also includes parts of Westchester County, is one of the few congressional districts in the country with a majority of nonwhites that is represented by a white person.