Longtime environmental and consumer protection activist Ralph Nader warned Elizabeth Warren and Bernie Sanders that their feud over whether Sanders made a sexist remark will only benefit their common rival in the Democratic presidential field.

“It doesn’t help the progressive cause for Bernie Sanders and Elizabeth Warren to be squabbling,” Nader, 85, tweeted Tuesday. “The Democratic Party corporatists want nothing more than divide and rule, so that their candidate Joe Biden reaps the benefits.”