If you attend enough conferences about antitrust policy, and I’ll impress you by saying that I have, you will inevitably hear two familiar words: “chilling” and “humble.” Any effort to prosecute antitrust cases, panelists say, creates a chilling effect on investment, preventing businesses from growing and thriving; and enforcers must be humble about how they interpret and apply the law.

Since the 1970s, conservative theorists from the University of Chicago have spoon-fed the legal theory behind such buzzwords to academics, judges, and regulators, and most have uncritically accepted it. In the Chicago School’s telling, mergers are good, enforcement is bad, and antitrust action is not to be trusted. The mindset is why we’re living in an age of monopoly, where four airlines run most of the routes, two providers serve up nearly all cable television, and two companies produce nearly all of the nation’s corn seeds.

Fiona Scott Morton, an economics professor at the Yale School of Management, is the last person I’d have expected to question this status quo. But in March, during a panel at American University called “The Antitrust Paradigm: Restoring a Competitive Economy,” I watched her tell researchers and academics, “‘Chilling’ means firms are fantastic ... and ‘humble’ means ‘I don’t want to enforce the antitrust laws.’”

Scott Morton didn’t always sound so radical. I’d heard her speak several times before that panel, and assumed that she, like antitrust experts in both parties, was deferential to big business. She’d worked under President Obama in the antitrust division of the Justice Department, which never followed up on a promise Obama made to family farmers to prevent agribusinesses from squeezing their profits and throwing them into financial ruin. The division also approved a spate of airline mergers and a deal between Ticketmaster and Live Nation that created a virtual monopoly in event ticketing.

While she may not have agreed with those decisions at the time, Scott Morton never spoke out against them, calling instead for “more research.” Not so long ago, she told me, she still believed in “incremental reform.”