ADVANCE FOR USE SUNDAY, AUG. 10, 2014, AND THEREAFTER- FILE - In this Aug. 10, 1964 file photo, President Lyndon B Johnson signs the Joint Resolution for the Maintenance of International Peace and Security, also known as the Gulf of Tonkin Resolution, backing his firm stand against aggression in Southeast Asia, in the East Room of the White House in Washington. 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, Johnson signed the resolution that historians call the crucial catalyst for deep American involvement in the Vietnam War. (AP Photo/John Rous, File)