In its 1996 decision, Seminole Tribe v. Florida, the Supreme Court, reversing itself, held that Congress lacks Article I power to abrogate states’ Eleventh Amendment immunity from suit in federal court. In exploring the decision’s ramifications, Professor Jackson contends that it may foreshadow more pervasive, and more troubling, shifts in the balance of power between state and federal governments, and among the federal, judicial, legislative, and executive branches. In particular, the Court’s dubious reasoning in Seminole Tribe may have severe repercussions on the federal courts’ ability to enjoin state officials from violating federal Iaw in the future. The availability of such equitable relief, under the so-called Ex parte Young doctrine, has long been accepted as a necessary counterbalance to the states’ Eleventh Amendment immunity from federal jurisdiction. While the new restrictions on Congress’s power would seem to make the availability of such relief more important than before, Professor Jackson examines how the Court’s unfortunate analysis in Seminole Tribe may presage a substantial limitation of the Ex parte Young doctrine in the federal courts. Professor Jackson concludes by articulating the dangers that such a course might pose to federal courts’ role in maintaining the rule of law and the supremacy of federal law.