President John F. Kennedy sits for a moment at White House microphones in Washington, after finishing his radio-television broadcast to the nation on July 26, 1963, on the nuclear test ban agreement initialed by negotiators in Moscow. In his deliberately cautious talk to the people, the president said that such a treaty would not resolve all conflicts or eliminate the dangers of war but it offered to all the world a welcome sign of hope. (AP Photo/John Rous) (John Rous/AP) “I speak … in a spirit of hope,” said President John F. Kennedy, beginning a policy address to the nation...