The U.S. Constitution also outlines general rules for relations between the states and other aspects of the states' relationship to the national government. Article IV of the Constitution is exclusively dedicated to these concerns.
- Section 1 explicitly requires the states to grant "full faith and credit" to "the public acts, records, and judicial proceedings" of the other states.
- Section 2 requires that each state respect the "privileges and immunities" that all citizens of the United States enjoy. This second section also requires that the states allow extradition of fugitives from the law (including slaves) from other states.
- Section 3 establishes general rules on the admission of new states.
- Section 4 establishes that the national government will ensure that a "republican form of government" (i.e., democratic government) exists in every state. This last section also guarantees the national government's protection of the states from foreign invasion or internal insurrection.