text: help!washington state law.i belive this practice was found un-constitutional.? local police have in the past made a practice of when they were behind someone,having no reason to pull the over,run their plates,to see if the regestered owner has a valid licence,then pulling the car over to see if that person happened to be driving.i know that this practice was stopped,atleast for a while.i belive it was found un-constitutional under the fouth amendment.is there any one out there that could shed some light on this for me please? if you read this you will find that the supreme court held it was a violation of the 4th and 14th amendment to even stop a car and check their registrations without cause. it's illegal!.  on certiorari, the united states supreme court affirmed. in an opinion by white, j., joined by burger, ch. j., and brennan, stewart, marshall, blackmun, powell, and stevens, jj., it was held that, (1) as a preliminary matter, the court had jurisdiction in the case at bar even though the delaware supreme court had held that the stop at issue not only violated the federal constitution but also a provision of the state constitution substantially similar to the fourth amendment, since the delaware supreme court had not rested its decision independently on the state constitution but had based its decision on the fourth and fourteenth amendments, having followed the approach, consistent with previous opinions of the delaware supreme court, of interpreting the state constitutional provision in terms of the breadth and scope of the fourth and fourteenth amendments, and (2) a policeman's stopping an automobile and detaining the driver in order to check the driver's license and the registration of the automobile constitute an unreasonable seizure under the fourth and fourteenth amendments, except in those situations in which there is at least an articulable and reasonable suspicion that a motorist is unlicensed, or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, such rule against random stops and detentions, however, not precluding a state from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion, such as, for example, the questioning of all oncoming traffic at roadblock-type stops.  blackmun, j., joined by powell, j., concurred, with the understanding that (1) the court's allowing spot checks that do not involve the unconstrained exercise of discretion would include, in addition to a roadblock stop for all traffic, other stops that were not purely random and that equate with, but are less intrusive than, a 100% roadblock stop, and (2) the court's decision was distinguishable, for purposes of constitutionality, from individualized random examinations by game wardens in the performance of their duties.