On March 3, 2015, the Supreme Court heard oral argument in City of Los Angeles v. Patel. This case presents two questions. The first question in this case is whether the Fourth Amendment permits facial challenges to municipal ordinances and statutes or only “as-applied” challenges. The second question is whether warrantless police searches of hotel guest registries, which include information that a guest is required by law to provide, are unconstitutional under the Fourth Amendment. -- To discuss the case, we have Prof. Nicholas Quinn Rosenkranz, who is a Professor of Law at the Georgetown University Law Center.