SEN. AMY KLOBUCHAR (D-Minn.) may figuratively have written the book on modern-day bipartisanship, and she’s literally writing the book on modern-day antitrust. She puts the two together in a bill that would reform competition policy for the 21st-century economy. The moderate but meaningful proposals provide a launchpad for cross-aisle cooperation, a goal of much of the senator’s legislative handiwork.

“The big technology companies are the glaring example of what’s going on right now in our economy, but they’re not the only example,” Ms. Klobuchar told us. The Competition and Antitrust Law Enforcement Reform Act doesn’t purport to target Silicon Valley titans in particular, yet it is designed to catch existing doctrine up to the realities of the digital age — specifically when it comes to Facebook, Google, Apple and Amazon (whose founder, Jeff Bezos, owns The Post). The laws need to be “as sophisticated as the companies that they’re trying to regulate,” Ms. Klobuchar says. That requires changes and clarifications reversing decades of damaging jurisprudence.

The bill’s aim isn’t to punish big companies for being big but to enable the Federal Trade Commission, the Justice Department and state attorneys general to bring more cases when merited — and to win them. That starts with increased funding for the agencies, which Republicans already support. From there, the legislation nudges the agencies on how to use that extra money: first and foremost, by challenging mergers. Judges have required too much certainty from enforcers to show that a merger will impede competition; the legislation introduces a risk-based approach instead. Judges have tended to assume mergers aren’t anticompetitive even in concentrated markets; the legislation would flip the presumption so that the most dominant companies must demonstrate the value of a merger.

These rules send courts “a message about Congress’s view of . . . the legislative history” of landmark antitrust laws, as Ms. Klobuchar put it. So does a confirmation that higher prices aren’t the only harm that can come from concentration: Quality and innovation matter, too. A thornier provision in the bill treats exclusionary conduct on the part of the same dominant companies as anticompetitive unless shown otherwise. The proof of this pudding will be in the adjudicating: Certainly, some exclusive deals and even some self-preferencing bring benefits to consumers. Such practices may merit scrutiny, but not automatic prohibition. The question of precisely which actions by gatekeeper firms are insidious and which are innocuous remains unanswered, and answering it remains essential.

There’s more in the jam-packed bill, including civil fining authority for first-time antitrust violations (a no-brainer for deterring malfeasance) as well as retrospective merger reviews and an FTC study on consolidation (no-brainers, too, for understanding the problem the government hopes to solve). The bevy of ideas may mean more that’s controversial, but it also should mean more that creates consensus. This is what legislating looks like — and it is much preferable to partisan point-scoring, or, as Ms. Klobuchar described last year’s castigatory CEO hearings over Zoom, “throwing popcorn at a movie screen.”

Read more: