Twenty-six years ago, in Whren v. United States, 517 U.S. 806 (1996), the Supreme Court held that, where a police officer has probable cause to believe a traffic infraction has been committed, the stop is lawful under the Fourth Amendment even though the underlying reason for a vehicular stop might have been to investigate some other matter, or even if it was predicated on racial profiling. The court rejected any effort to tie the legality of an officer's conduct to his or her primary motivation or purpose in making the stop, deeming irrelevant whether a reasonable police officer would have made the stop.