ADVANCE FOR USE SUNDAY, AUG. 10, 2014, AND THEREAFTER- FILE - In this Aug. 10, 1964 file photo, President Lyndon B. Johnson speaks in the East Room of the White House in Washington, as leaders of Congress stand by his desk for a ceremonial signing of the Congressional resolution, also known as the Gulf of Tonkin Resolution, backing his firm stand against aggression in Southeast Asia. Fifty years ago Johnson signed the resolution that historians call the crucial catalyst for deep American involvement in the Vietnam War. From left Rep. Carl Albert, D-Okla., Sen. Hubert Humphrey, D-Minn., Rep. Charles Halleck, R-Ind., Sen. Everett Dirksen, R-Ill., House Speaker John McCormack and Sen. J.W. Fulbright, D-Ark. In right background are Sen. George Aiken, R-Vt., and Sen. George Smathers, D-Fla. (AP Photo/John Rous, File)