SCOTUSblog flags a pending cert petition on an interesting Fourth Amendment question: What limits, if any, does the Fourth Amendment place on the use of a trained drug-sniffing dog to approach the front door of a home? The police might do this to see if the dog will alert for the presence of narcotics in the home, which might then be used to help show probable cause and obtain a warrant to search it. Under Illinois v. Caballes, the use of the dog around a car is not a “search” and therefore outside the Fourth Amendment. The question is, does...