The activist chairwoman of the Federal Trade Commission has taken long-anticipated action against the tech industry. Overriding staff objections, Lina Khan filed a federal lawsuit that seeks to stop social media giant Meta — formerly known as Facebook, Inc. — from buying virtual reality company Within, the maker of a popular fitness app. Khan rose to fame in the progressive legal community by arguing for an expansion of antitrust enforcement to target what she says are the novel business arrangements and practices of large tech companies. The Meta suit comes more than a year into Khan’s tenure at the helm of the FTC.

Several media reports have pointed out that the agency’s staff recommended against challenging the acquisition, but Khan proceeded anyway.