WASHINGTON, D.C. - The U.S. Supreme Court on June 24 refused to hear an appeal of a lower federal court's ruling that the application of the discretionary function exception (DFE) to the Federal Tort Claims Act (FTCA) completely insulates the U.S. government from liability for claimants' Hurricane Katrina flood damage (Kent Lattimore, et al. v. United States, et al., No. 12-1092, U.S. Sup.).