The so-called "Marshall Trilogy" (after Chief Justice John Marshall), comprising Johnson vs. M'Intosh (1823), Cherokee vs. Georgia (1831), and Worcester vs. Georgia (1831), is key to the history of tribe-state-union relations. Marshall's ruling in the Cherokee cases established the tribes' sovereign immunity from state law; but his language emphasized a larger truth--namely, that some nations were more sovereign than others, and that the U.S. government was the final authority on Indian affairs.

Marshall wrote in Johnson vs. M'Intosh that the Indians had a "right to such a degree of sovereignty, as the circumstances of the people would allow them to exercise." The "circumstances of the people" were articulated thus by Marshall: "Indian inhabitants were to be considered merely as occupants, to be protected ... but ... incapable of transferring absolute title to others."

In Cherokee vs. Georgia, Marshall wrote that "the relations established between the United States and the Cherokee nation ... are committed exclusively to the government of the union." Worcester vs. Georgia, while expressly limiting the states' authority, emphasized the union's: "The "Cherokee nation, then, is a distinct community occupying its own territory, with boundaries accurately described, in which the laws of Georgia have no force, and which the citizens of Georgia have no right to enter, but with the assent of the Cherokees themselves, or in conformity with treaties and with the acts of congress. The whole intercourse between the United States and this nation, is, by our constitution and laws, vested in the government of the United States."