The U.S. Supreme Court has ruled that police conducted a search within the meaning of the Fourth Amendment when they used a police dog to sniff for drugs on the porch of a home. Conservative Justices Antonin Scalia and Clarence Thomas joined with three of the court’s liberals to form a majority. The case is “a straightforward one,” Scalia said in his majority opinion (PDF), because police had gathered evidence in the vicinity immediately outside the house—the area known as the curtilage. Justice Elena Kagan wrote a concurring opinion joined by Justices Ruth Bader Ginsburg and Sonia Sotomayor. Kagan said the use of the drug dog was a search based on privacy as well as property grounds.