In the United States v. Ortiz case of 1974, the U.S Supreme Court ruled that warrantless searches by border patrol officers at permanent checkpoints located away from the border or its functional equivalent were in violation of the Fourth Amendment's protection against unreasonable searches and seizures. The defendant, Mr. Ortiz, had been stopped at a checkpoint approximately 66 miles north of Mexico where his vehicle was searched without a warrant leading to discovery and seizure of illegal immigrants. He challenged this action arguing it violated his constitutional rights under the Fourth Amendment. In their decision, justices unanimously agreed with him stating that such stops for search purposes required either consent or probable cause supported by a warrant.

In the dissenting opinion for United States v. Ortiz, Justice William Rehnquist disagreed with the majority's decision that border patrol agents must have probable cause to conduct searches at permanent checkpoints located away from the border. He argued that these types of searches were not a violation of Fourth Amendment rights against unreasonable search and seizure because they served a vital national interest in controlling immigration. Furthermore, he contended that such stops are minimally intrusive given their routine nature and limited scope. In his view, requiring probable cause would severely hamper law enforcement efforts to control illegal immigration as it is often impossible for officers to determine whether there is reasonable suspicion or probable cause before stopping vehicles at these checkpoints.