FILE - In this Aug. 14, 1964 file photo, a U.S. jet plane roars off the deck of the aircraft carrier Constellation in the Tonkin Gulf, Vietnam. Fifty years ago Sunday, Aug. 10, 2014, reacting to reports of a U.S. Navy encounter with enemy warships in the Gulf of Tonkin off Vietnam, President Lyndon Johnson signed a resolution that historians call the crucial catalyst for deep American involvement in the Vietnam War. (AP Photo/Pool, File)