Indian tribes possess a special status under U.S. law. In 1787, the new U.S. Constitution reserved for the federal government the power to “regulate commerce” with foreign nations, among states, and with Indian tribes. In 1831 and 1832, two U.S. Supreme Court decisions determined that tribes in the U.S. were “independent political communities” with “original natural rights” that preceded European colonization. Certain jurisdictional rights were declared to be ones with which no state could interfere. In the last century, judicial rulings began to recognize tribes’ sovereign immunity from lawsuits as one aspect of this sovereignty. As a result of these laws, a state’s regulation of tribal activities-including casinos-generally is limited to what is authorized under (1) federal law and (2) federally approved agreements between tribes and a state.