In a case closely watched by law enforcement nationwide, the U.S. Supreme Court agreed Friday to decide whether a Florida police dog's sniff outside the front door of a house with a marijuana growing operation is an illegal search.

Florida Attorney General Pam Bondi wants the justices to reverse a state Supreme Court decision that the K-9's sniff runs afoul of the Fourth Amendment protection against illegal search and seizure. Eighteen states and the territory of Guam have filed a brief in support of Bondi's position, concerned that other state courts might start issuing similar decisions.

"If the Florida Supreme Court's decision stands, it could have a profound chilling effect on law enforcement efforts to combat illegal drugs," the states' filing says. "The Florida Supreme Court's decision jeopardizes the states' ability to use this crucial tool to discover illegal drugs prior to their distribution."

The case arose from the December 2006 arrest of Joelis Jardines at a Miami-area house where 179 marijuana plants were confiscated. Miami-Dade Police Department officers obtained a search warrant after one of their dogs, a chocolate Lab named Franky, detected the odor of pot from outside the front door.

The trial judge threw out the evidence, agreeing with Jardines' attorney that the dog's sniff was an unconstitutional intrusion into the home. An appeals court reversed that ruling, but the state Supreme Court sided in April with the original judge.