ANALYSIS: Meta Suit Shows FTC Grappling With a Barn Door Problem

The Federal Trade Commission’s lawsuit to stop Meta Platforms Inc. from acquiring virtual fitness company Within Unlimited Inc. seems like a long shot. It’s aimed at a broader problem, however, that antitrust enforcers will have to solve if they intend to keep platform markets open and innovative.

The problem is that antitrust law is fundamentally backward-looking: It looks at existing market conditions, uses established economic methods to analyze them, and decides whether a practice was anticompetitive based on legal precedent set in prior cases. That is at odds with the growing need for enforcers to predict where nascent or fast-changing ...