As a general matter, the Constitution limits the government but not the private sector. Known as the “state action” doctrine, the idea that constitutional constraints apply only when public entities are primarily or substantially involved has been developed by the U.S. Supreme Court in scores of cases. This Article argues that the fundamental inadequacy of and dissatisfaction with the state action doctrine arises from the Court’s unwillingness to admit that state action principles are not transsubtantive—that the principles play out differently depending on the particular constitutional claim being asserted. The Article surveys state action rulings to argue that functional considerations—rather than a formalistic, abstract, and uniform quality of “stateness”—should and do dictate when the state action requirement is satsified and the Constitution’s limits are held to apply. The Article then analyzes the Supreme Court’s 1988 decision in NCAA v. Tarkanian to explore how a functionalist analysis might play out in the context of the NCAA and other athletic regulatory bodies.