Heien v. North Carolina

North Carolina (plaintiff) charged Nicholas Heien (defendant) with drug offenses based on cocaine found in his car. An officer had stopped the car because only one of its two brake lights worked, believing that violated state law. The North Carolina Court of Appeals held that the law required only one working brake light, so the stop was unjustified; the state supreme court reversed, upholding the stop as based on a reasonable mistake of law.

Whether a mistake of law can give rise to the reasonable suspicion needed to uphold a warrantless traffic stop under the Fourth Amendment.