Fourteen years ago, in C & A Carbone, Inc. v. Town of Clarkstown, the U.S. Supreme Court held that a local government had unconstitutionally discriminated against interstate commerce when it forced its citizens to purchase all waste-transfer services from a single local private supplier. In a recent decision, United Haulers Ass'n v. Oneida- Herkimer Solid Waste Management Authority, the Court refused to extend the principle of Carbone to a law that required citizens to purchase these same services from a local government-operated facility. The Court thereby engrafted on the dormant Commerce Clause a new state-selfpromotion exception, which receives its first extended treatment in this Article. I begin by identifying the many contexts in which this exception may take hold, touching in the process on subjects as diverse as public/private joint ventures, utility regulation, the fixing of user fees, and state tax rules that are tied to government operations. I then explore the often subtle ways in which the state-self-promotion exception will interact with existing features of dormant Commerce Clause law and propose guiding principles for deciding difficult questions that the exception presents. Finally, I examine the spillover effects that this innovation may have on current debates over both the legitimacy and scope of the dormant Commerce Clause and the proper reach of Congress's power to regulate commercial matters. My analysis reveals that the state-self-promotion exception is not a constitutional sideshow. Rather, it is a major new doctrinal initiative that is destined to have a far-reaching-though now greatly underappreciated impact.