Progressive New York Rep. Jamaal Bowman lost his Democratic primary to a moderate challenger, NBC News projects, following a bitter and expensive race that exposed the party’s divisions.

Westchester County Executive George Latimer defeated Bowman, a member of “the squad” and one of the most vocal critics of Israel in Congress. The contest attracted more ad spending than any House primary in history. Bowman is the first incumbent Democratic lawmaker to lose a primary this election cycle.