In the United States v. Cortez et al., 1980, the Supreme Court ruled on a case involving Fourth Amendment rights and reasonable suspicion for law enforcement stops. Border patrol agents had stopped two men, Cortez and Ricardo Delgado, in their vehicle near the Mexico-Arizona border based on a profile of typical characteristics of alien smugglers. The agents found illegal aliens in the vehicle and arrested both men. The defendants argued that this stop violated their Fourth Amendment rights against unreasonable searches and seizures as there was no probable cause for it. However, the Supreme Court held that while individual factors may be insufficient to create reasonable suspicion, taken together they can amount to reasonable suspicion justifying an investigatory stop if they paint a picture of suspicious behavior when viewed through the lens of law enforcement experience.

In the dissenting opinion for United States v. Cortez et al., Justice Brennan, joined by Justice Marshall, argued that the majority's decision to uphold the Border Patrol agents' stop and search of Cortez was a dangerous erosion of Fourth Amendment protections against unreasonable searches and seizures. They contended that reasonable suspicion should be based on specific, articulable facts rather than vague hunches or profiles. The dissent criticized the majority for allowing law enforcement officers to make stops based on broad generalizations about certain groups of people (in this case, illegal immigrants), which they believed could lead to racial profiling and other forms of discrimination. Furthermore, they disagreed with the majority's assertion that an officer can develop "particularized" suspicion from observing behavior that is innocent in itself but suspicious when considered as part of a larger pattern.