This article discusses how to move antitrust enforcement forward in a constructive manner during a time of widespread and growing concern over the political and economic power of large corporations in the United States. Three themes are emphasized. First, a body of economic evidence supports more vigorous merger enforcement in the United States. Tighter merger control can be achieved by utilizing the existing legal presumption against highly concentrating mergers. Second, close antitrust scrutiny is appropriate for today's largest and most powerful firms, including those in the tech sector. Proper antitrust enforcement regarding unilateral conduct by dominant firms should continue to focus on identifying specific conduct that harms customers or disrupts the competitive process. Third, while antitrust enforcement has a vital role to play in keeping markets competitive, antitrust law and antitrust institutions are ill suited to directly address concerns associated with the political power of large corporations or other public policy goals such as income inequality or job creation.