In the case of Dooley v. United States in 1900, the U.S Supreme Court ruled on a dispute involving import duties collected by the U.S government from goods imported into Puerto Rico from New York after Spain ceded Puerto Rico to the U.S following the Spanish-American War but before Congress enacted legislation for its governance. The plaintiff, Francis H. Dooley, argued that these duties were unconstitutional as they violated uniformity clause which prohibits non-uniform taxes across states and territories of America. The court held that while Puerto Rico was indeed under American control at this time, it had not been formally incorporated into America as a territory and thus did not fall within revenue clauses of Constitution requiring uniform taxation. Therefore, collection of import duties was deemed constitutional since it didn't violate any existing laws or provisions regarding taxation within recognized territorial limits of United States.

In the dissenting opinion for Dooley v. United States, Justice John Marshall Harlan argued that the Constitution of the United States should apply to all territories under its control, regardless of whether they were destined for statehood or not. He maintained that once a territory is acquired by the U.S., it becomes part of the country and thus should be subject to all constitutional provisions including those related to taxation. According to him, imposing duties on goods transported from Puerto Rico (a U.S. territory) into mainland America was unconstitutional as it violated uniformity clause in Article I Section 8 which requires taxes and duties be uniform across all states and territories within U.S jurisdiction. He disagreed with majority's view that only "incorporated" territories are fully covered by constitution while "unincorporated" ones aren't; stating there's no such distinction in constitution itself.