The calls to break up Facebook have reached a fever pitch, and the Federal Trade Commission appears to be listening. But in the rush to “do something” about Facebook, the FTC may be on the verge of a regulatory flip-flop that raises fundamental questions about its power to retroactively kill mergers that it approved years ago, including Facebook’s 2012 acquisition of Instagram.

In the past year, Chris Hughes, a Facebook co-founder, proclaimed that “It’s Time to Break Up Facebook” because CEO Mark Zuckerberg’s “influence is staggering.” Sen. Elizabeth Warren, D-Massachusetts, ran for president on a platform of breaking up “Big Tech” and “unwinding” Facebook’s mergers with Instagram and WhatsApp. Sen. Josh Hawley, R-Missouri, reportedly told Mark Zuckerberg to sell Instagram and WhatsApp. And break-up proponent Tim Wu has suggested that Zuckerberg committed a felony when Facebook acquired Instagram. Most recently, a House antitrust subcommittee report dedicated to Big Tech and competition in digital markets called for reshaping antitrust enforcement in ways that would uproot decades of precedent.