The Supreme Court closed this millennium with a virtual celebration of state sovereignty, protecting state authority from the reach of congressional power in several significant ways. In a pair of cases, Seminole Tribe v. Florida1 and Alden v. Maine,2 the Court held that states enjoy a constitutional immunity from being sued without their consent. In Seminole Tribe, the Court opined that "the background principle of state sovereign immunity embodied in the Eleventh Amendment"3 protects states from unconsented suits in federal court. In Alden, the Court held that this principle is not merely embodied in the Eleventh Amendment but rather is also rooted in "fundamental postulates implicit in the constitutional design,"4 and as such it protects states from unconsented suits in their own state courts as well.
Caminker, Evan H. "State Immunity Waivers for Suits by the United States." Mich. L. Rev. 98, no. 1 (1999): 92-137.