Print The Federal Trade Commission and the attorneys general of 46 states filed lawsuits Wednesday seeking what amounted to a do-over on Facebook — the chance to reject two acquisitions that helped make the social network the behemoth it is today. Those acquisitions — the $1-billion purchase of the mobile picture-sharing network Instagram in 2012 and the $19-billion purchase of the messaging service WhatsApp two years later — absorbed fledgling companies that had threatened to draw users away from Facebook. Yet the FTC initially approved both mergers, and the states did not try to stop them at the time they were announced. Facebook will probably make hay out of those approvals as the case moves forward, but this is more than an exercise of 20/20 hindsight. The state and FTC lawsuits allege that the purchases fit into a troubling pattern of steps by Facebook to buy up or beat down rivals. Those allegations, based on documents and other evidence gathered by state and federal investigators, speak to the kind of anti-competitive tactics that might be ignored in a start-up but can’t be countenanced in a market-leading firm.