Measured antitrust enforcement and a more comprehensive regulatory regime can ensure that we continue to benefit from digital markets. In attempting to increase competitiveness, however, enforcers will have to first overcome hostile antitrust jurisprudence and lengthy procedures.  After years of timid enforcement against powerful online platforms, and silence from Congress, we are witnessing the awakening of antitrust in the United States. At last, antitrust enforcers have accepted that digital...