The Biden administration’s aggressive set of antitrust enforcers have created powerful enemies: in big business, in media, in academia, and in Washington. For the most part, the main antagonists of the Federal Trade Commission and the Department of Justice’s Antitrust Division have been Republicans, though there are a few Khanservatives. But now, pro-corporate Democrats are getting in on the act, targeting an obscure but critical policy designed to give enforcers the information they need to judge proposed corporate mergers.