Justices continue on path of strengthening constitutional protections against `unreasonable search and seizure'

WASHINGTON-The Supreme Court ruled 6-3 on Tuesday police can't prolong a routine traffic stop to allow a drug-sniffing dog to search the vehicle unless they have a reasonable suspicion of uncovering contraband.

The case is the latest to see the justices reinvigorate constitutional protections against "unreasonable searches and seizures," following recent decisions that rejected warrantless cellphone searches and installation of GPS trackers.

Tuesday's ruling tightens the parameters police should follow when using drug-sniffing dogs during a traffic stop, building on a 2005 precedent allowing the drug searches while stressing such procedures become unlawful if a motorist is detained solely to conduct the search.

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