The U.S. Supreme Court case of Buttfield v. Bidwell in 1903 centered around the issue of whether or not a tax imposed on goods imported from Puerto Rico to New York was constitutional, following the Spanish-American War when Puerto Rico became a territory of the United States. The plaintiff, Julia Buttfield, argued that this tax violated Article I Section 8 Clause 1 and Article I Section 9 Clause 5 of the Constitution which prohibits Congress from imposing taxes on articles exported from any state. However, the court ruled against her by deciding that territories were not included under these clauses as they are not states within the Union but possessions belonging to it. This decision established what is known as "the doctrine of territorial incorporation", stating that only fundamental rights apply to inhabitants residing in unincorporated territories unless extended by Congress.

In the dissenting opinion for Buttfield v. Bidwell, Justice John Marshall Harlan argued that the Constitution should apply to all territories under U.S. control, regardless of whether they were destined for statehood or not. He believed that Congress did not have unlimited power over these territories and was bound by constitutional restrictions in its governance of them. This included providing equal protection rights and due process to their inhabitants. Harlan contended that Puerto Rico had become a part of the United States upon ratification of the Treaty of Paris in 1898, thus making it subject to full constitutional protections immediately rather than being considered an "unincorporated" territory with limited application of Constitutional rights as majority opined.