The fourth in this quartet is the theory of state sovereignty ("states' rights"), also known as the "Calhoun doctrine" after the South Carolinian political theorist and statesman John C. Calhoun. Rejecting the arguments for federal authority or self-government, state sovereignty would empower states to promote the expansion of slavery as part of the federal union under the US Constitutionand not merely as an argument for secession. The basic premise was that all authority regarding matters of slavery in the territories resided in each state. The role of the federal government was merely to enable the implementation of state laws when residents of the states entered the territories. Calhoun asserted that the federal government in the territories was only the agent of the several sovereign states, and hence incapable of forbidding the bringing into any territory of anything that was legal property in any state. State sovereignty, in other words, gave the laws of the slaveholding states extra-jurisdictional effect.