The Fourth Amendment protects citizens from unlawful searches and seizures. Once the officer initiates a traffic stop, the driver and all passengers have been "seized" under the 4th amendment.The Fourth Amendment is the part of the Bill of Rights that prohibits "unreasonable searches and seizures. " But — what's unreasonable? The 4th amendment prohibits unreasonable search and seizure. Article identifies and discusses several problems with consensual search doctrines and the particularly harmful effect on individuals with mental illness. As a general rule, the Fourth Amendment requires police to have a warrant to conduct a search. Legal scholarship discussing police use of force and constitutional law provides important evaluations of how courts have interpreted the Fourth Amendment. SEARCH AND SEIZURE:ATREATISE ON THE FOURTH AMENDMENT § 7.4(a) (6th ed. 2020). The police officer needs to show that there is a reasonable or articulable suspicion that there is criminal activity afoot, such as a traffic violation.