Antitrust enforcers on both sides of the Atlantic are grappling to get a handle on AI, a conference in Brussels heard yesterday. It's a moment that demands "extraordinary vigilance" and clear-sighted focus on how the market works, suggested top US competition law enforcers. From the European side, antitrust enforcers sounded more hesitant over how to respond to the rise of generative AI -- with a clear risk of the bloc's shiny new ex ante regime for digital gatekeepers missing a shifting tech target.