The US Supreme Court [official website] ruled [opinion, PDF] Tuesday in Florida v. Harris [SCOTUSblog backgrounder] that an alert from a well-trained narcotics detection dog certified to detect illegal contraband is sufficient to establish probable cause for the search of a vehicle. The ruling reversed the Florida Supreme Court [official website], which held [opinion, PDF] that training alone is insufficient to establish the reliability of the dog and that further information, such as field performance records indicating how often the dog falsely alerted, is required. In order for police officers to establish probable cause under the Fourth Amendment [text], there must be a "fair probability" that the contraband or evidence of a crime is present, which is determined by the "totality of the circumstances." Writing for a unanimous court, Justice Elena Kagan noted that while the Supreme Court has rejected a rigid rule in favor of a flexible test, the "Florida Supreme Court flouted this established approach to determining probable cause ... [and] created a strict evidentiary checklist, whose every item the State must check off." Rejecting the "comprehensive documentation" requirement imposed by the Florida Supreme Court, the US Supreme Court established that a dog's satisfactory performance in a certification or training program can sufficiently establish the trustworthiness of its alert and held that in this instance, the defendant failed to introduce evidence that the certification or training was inadequate.
In January 2012 the court granted certiorari in the related case of Florida v. Jardines [SCOTUSblog backgrounder] to determine whether the use of a drug-sniffing dog at the front door of a house is a search under the Fourth Amendment requiring probable cause. The Florida Supreme Court ruled [opinion, PDF] that such a search did require probable cause. The Supreme Court heard oral arguments [transcript, PDF; JURIST report] in the case in October, and a decision is pending.