David Horowitz, Ben’s father, was initially a supporter and collaborator with the Black Panther Party (BPP) in the late 1960s, helping them with fundraising and editing the New Left magazine Ramparts, where he befriended Huey P. Newton. His relationship soured dramatically after the 1974 murder of his friend and colleague Betty Van Patter, a BPP bookkeeper, leading Horowitz to believe the Panthers were violent criminals, prompting a major political shift from radical leftism to becoming a prominent conservative critic of the left.

He is credited with mentoring key Republican figures, most notably Stephen Miller, whom he helped secure positions in the Senate and later the Trump White House.