The State of Washington v. Thomas L. Ladson

Summary

The court held that pretextual traffic stops violate article I, section 7 of the Washington Constitution when an officer uses a traffic infraction as a pretext for an unrelated criminal investigation. It concluded that the actual investigative purpose was not exempt from the warrant requirement, making the initial seizure unlawful and requiring suppression of the evidence discovered during the stop and ensuing searches. Justice Madsen, dissenting, would have held that an officer's motive does not invalidate a traffic stop supported by probable cause, while limiting any detention or search to the traffic offense absent independent justification.