The Supreme Court in DeLima v. Bidwell had decided that ever since Puerto Rico had been acquired by the United States from Spain in the Treaty of Paris (1898), normal customs levied on imports from foreign countries did not apply to imports from Puerto Rico since it had ceased to be a foreign country.

However, the court was careful to note that the constitutional guarantees of a citizen's rights of liberty and property were applicable to all and "cannot be under any circumstances transcended", according to Justice Edward Douglass White's concurring opinion.

One of two dissenting opinions was written by Justice John Marshall Harlan, who would have held that Congress was always bound to enact laws within the jurisdiction of the Constitution: "This nation is under the control of a written constitution, the supreme law of the land and the only source of the powers which our government, or any branch or officer of it, may exert at any time or at any place."

I take leave to say that, if the principles thus announced should ever receive the sanction of a majority of this court, a radical and mischievous change in our system will result.

It will be an evil day for American Liberty if the theory of a government outside the Supreme Law of the Land finds lodgment in our Constitutional Jurisprudence.