The United States v. Rene Martin Verdugo-Urquidez case in 1989 revolved around the question of whether the Fourth Amendment, which protects against unreasonable searches and seizures, applies to non-citizens outside U.S. territory. The defendant, a Mexican citizen suspected of drug trafficking was arrested by Mexican authorities and extradited to the U.S., where DEA agents without a warrant searched his residences in Mexico for evidence. The Supreme Court ruled 6-3 that the Fourth Amendment did not apply because it only extends its protections to those who have developed substantial connections with the U.S., which Verdugo-Urquidez had not done so at any point during his arrest or trial process.

In the dissenting opinion for United States v. Verdugo-Urquidez, Justice Brennan argued that the Fourth Amendment's protection against unreasonable searches and seizures should apply to all actions by U.S. authorities, regardless of where they occur or who they involve. He believed that this principle was a fundamental aspect of American law and disagreed with the majority's view that constitutional protections only applied within U.S. borders or to people with significant voluntary connections to the U.S.. Furthermore, he criticized their reliance on an "unprecedented" interpretation of what constitutes 'the people' protected under the Constitution as being too narrow and inconsistent with historical understanding. In his view, it was not necessary for someone to have substantial ties with America in order for them to be treated fairly under its laws; rather, anyone subjected to action by American officials should benefit from these protections.