For several years, an increasing number of commentators have been expressing concern that the U.S. has a growing market power problem. Further that dysfunction in the U.S. antitrust institutions, and their failure to protect competition, has damaged the economy. These concerns have led to intensified demands for a redirection of antitrust policy, which range from calls for substantially more to be done with the existing system, to calls for the creation of a new regulatory authority, to calls for a “root and branch” transformation of the antitrust system that would embrace objectives beyond enhancing the welfare of citizens as buyers of goods and services. This Article outlines the principal flaws that this commentary attributes to U.S. antitrust policy (the “crisis in antitrust”), and some of the proposals offered to restore antitrust policy as a central tool of economic control. Its main purpose is not, however, to debate the condition of competition in the US economy or the substantive merits of the measures proposed. Rather, its objective is to identify the magnitude of the implementation challenges that the proposals for a major expansion of the U.S. antitrust program create and the policy implementation challenges that stand between these soaring reform aspirations and their effective realisation in practice. The paper thus takes the various reform recommendations at face value, and asks what must be done to land them. The paper suggests that even though these “implementation” issues are significant, they have been too quickly overlooked in the commentary as technical details to be (easily) addressed once the high level concepts of a bold antitrust program have been settled. In our view the failure to focus on this important matter, risks serious disappointment by creating a potential chasm between elevated policy commitments and the capacity of responsible public institutions (competition agencies, new regulators and the courts) to produce expected outcomes. The paper consequently acknowledges and addresses this implementation blindside. It analyses the important impediments that are likely, if not carefully addressed, to hamper delivery of the current proposals to undertake a more ambitious antitrust program and proposes ways to overcome them with, or without, new powers from Congress.