Patrick Moran, who was his dad's field director, resigned Wednesday after the video, released by conservative activist James O'Keefe, showed him discussing how to falsify certain documents to vote on behalf of about 100 Virginians, Politico reported.
"In reference to the 'O'Keefe' video, at no point have I, or will I ever endorse any sort of illegal or unethical behavior," the younger Moran said. "At no point did I take this person seriously. He struck me as being unstable and joking, and for only that reason did I humor him."
Looking back, Moran said, "I should have immediately walked away, making it clear that there is no place in the electoral process for even the suggestion of illegal behavior, joking or not."
He said he stepped aside because "I do not want to be a distraction during this year's critical election."
"Patrick is well-liked and was a well-respected member of the campaign team," Moran's campaign said in a statement. "This incident, however, was clearly an error in judgment. The campaign has accepted Patrick's resignation, effective immediately."
The taped conversation occurred Oct. 8 in Arlington, Va., Politico said
The son's resignation came a day after Moran, along with Virginia Democratic Reps. Gerry Connolly and Bobby Scott, wrote to Attorney General Eric Holder, asking him to investigate voter fraud allegations that were tied to a GOP-allied firm.