Abstract: The U.S. Supreme Court’s Supremacy Clause jurisprudence has reached a confusing junction. The Court recently declined to say whether the Supremacy Clause confers a cause of action for federal court litigants. As a result, lower courts and litigants are caught between conflicting doctrines: one that suggests and one that denies that the Supremacy Clause confers causes of action. Neither line of cases definitively answers the question. A cause of action is necessary for a federal court plaintiff to bring suit. This Note explores whether potential plaintiffs should be able to rely on the Supremacy Clause when applicable federal law does not otherwise confer a cause of action. Navigating the history of the Supremacy Clause, the contours of dueling lines of precedent, and policy ramifications, the Note concludes that, in the midst of the confusion, state defendants have a strong argument that the Supremacy Clause does not confer plaintiffs a cause of action.