Article Four of the United States Constitution

The United States Constitution, ratified in 1788, never uses the words "slave" or "slavery", but recognized its existence in the so-called fugitive slave clause (Article IV, Section 2, Clause 3), the three-fifths clause, and the prohibition on prohibiting importation of "such Persons as any of the States now existing shall think proper to admit" (Article I, Section 9).

The Privileges and Immunities Clause (U.S. Constitution, Article IV, Section 2, Clause 1, also known as the Comity Clause) prevents a state from treating citizens of other states in a discriminatory manner.

Organized territories are lands under federal sovereignty (but not part of any state) which were given a measure of self-governance by Congress through an organic act subject to the Congress's plenary powers under the territorial clause of the Constitution's Article Four, section 3.

Admission to the Union is provided by the Admissions Clause of the United States Constitution in Article IV, Section 3, Clause 1, which authorizes the United States Congress to admit new states into the Union beyond the thirteen states that already existed when the Constitution came into effect.

The earlier Fugitive Slave Act of 1793 was a Federal law that was written with the intent to enforce Article 4, Section 2, Clause 3 of the United States Constitution, which required the return of escaped enslaved people.

The Fugitive Slave Clause in the United States Constitution, also known as either the Slave Clause or the Fugitives From Labor Clause, is Article IV, Section 2, Clause 3, which requires a "person held to service or labor" (usually a slave, apprentice, or indentured servant) who flees to another state to be returned to their master in the state from which that person escaped.

The political ideals have been discussed since before the concept of republic was introduced legally by Article Four of the United States Constitution.

Article IV, Section 3, Clause 2 of the U.S. Constitution grants to the United States Congress the responsibility of overseeing the territories.

Pursuant to the Property Clause of the United States Constitution (Article 4, section 3, clause 2), the Congress has the power to retain, buy, sell, and regulate federal lands, such as by limiting cattle grazing on them.

Article IV, Article V, and Article VI embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the shared process of constitutional amendment.