Courts have identified numerous exceptions to the Fourth Amendment’s search warrant requirement, meaning that law enforcement may conduct a search without first obtaining a warrant if they can demonstrate that the situation falls under a recognized exception. They must still demonstrate probable cause to believe that the search would yield contraband or evidence of criminal activity. The “border search exception,” however, goes further than most exceptions. It states that law enforcement, specifically the U.S. Border Patrol and U.S. Customs and Border Protection (CBP), can conduct searches of people and property entering the U.S. without a warrant, and without probable cause under some circumstances. Two Texas drug crime-related searches and seizures at a border crossing in early 2017, using high-tech imaging equipment, demonstrate how searches at or near the border can be different from searches elsewhere.
The border search exception is based in part on the sovereign right to control entry to the country. The U.S. Supreme Court has held that customs officials may search mail and other items arriving at the border without a warrant. United States v. Ramsey, 431 U.S. 606 (1977). With regard to searches of people and their property, the court has held that people have a lessened expectation of privacy at border crossings. Florida v. Royer, 460 U.S. 491, 515 (1983). Law enforcement can stop vehicles at fixed checkpoints for the purpose of immigration enforcement, even without any specific suspicion about individual vehicles, and they can refer some vehicles to a “secondary inspection area.” United States v. Martinez-Fuerte, 428 U.S. 543, 563 (1976).
Congress has given immigration officials the authority to perform these types of immigration enforcement functions up to 100 miles from international borders within the U.S. 8 U.S.C. § 1357(a)(3). When law enforcement officials are not operating out of a fixed checkpoint, such as by pulling over individual vehicles on public roads, the Supreme Court has held that they must be able to demonstrate probable cause. Almeida-Sanchez v. United States, 413 U.S. 266 (1973). Fixed checkpoints therefore provide law enforcement with their greatest amount of power to conduct warrantless searches.