United States v. Brignoni-Ponce, 422 U.S. 873 (1975), was a case in which the Supreme Court determined it was a violation of the Fourth Amendment for a roving patrol car to stop a vehicle solely on the basis of the driver appearing to be of Mexican descent.

[1] A roving patrol car must have articulable facts that allow for an officer to have a reasonable suspicion that the person is carrying illegal aliens beyond their ethnicity.

On March 11, 1973, the checkpoint had been closed because of inclement weather so the officers sat on the side of the highway in their vehicle with their headlights facing northbound traffic.

The second was Section 287 (a) (3) of the Act, 8 U. S. C. § 1357 (a) (3), which authorizes agents, without a warrant, to search cars traveling near the border that are suspected to have or are transporting persons trying to enter the country illegally.

According to the precedent set in Terry v. Ohio and Adams v. Williams, under appropriate circumstances, a roving patrol may perform a limited search and seizure without having probable cause to arrest the person.

His last-known arrest was on February 25, 1981, six years after his Supreme Court case was decided, at a San Clemente checkpoint, for smuggling thirteen illegal aliens.

Ironically, Brignoni-Ponce was born in Puerto Rico, not of Mexican descent as suspected in his initial stop by the Border Patrol, and is an American citizen.