“A smart boy and a bad influence.” That is how Robert F. Kennedy Jr. is described by Martin Peretz, the former owner of the New Republic, who taught Kennedy at Harvard. Mr. Peretz’s new memoir, “The Controversialist,” reports that Kennedy’s best friend at Harvard was Eric Breindel, who went on to become the brilliant editorial page editor of the New York Post.

“Eric liked the Kennedys, he was drawn to them, and he and Bobby Kennedy became drug mates at Harvard,” Mr. Peretz writes. Norman Podhoretz, the former editor of Commentary, was quoted in New York magazine after Breindel’s death in 1998 at age 42. Breindel “was mixed up with the Kennedy kids Bobby and David, and they were junkies,” Mr. Podhoretz said then. David Kennedy died in 1984 at age 28; that same year, Bobby Kennedy pleaded guilty to a heroin possession charge.