Last month, the FBI admitted it had used surveillance drones in domestic airspace but refused to disclose specific details. Now, after pressure from Sen. Rand Paul, R-Ky., the bureau has been forced to come clean. In a recent letter to Paul, published on the senator’s website Thursday, the FBI acknowledges that it has used drones domestically in 10 cases in response to a “specific, operational need.” The bureau says that, since late 2006, it has used unmanned planes for surveillance to support missions related to kidnappings, search and rescue operations, drug interdictions, and fugitive investigations. On eight occasions the drones...