CBS Evening News a one-evening test broadcast on August 19, 1965, before permanently switching to the format on January 31, 1966. Cronkite's prime time special report, "Who, What, When, Where, Why", broadcast on February 27, 1968, ended with his declaration that the United States could only hope for a stalemate in Vietnam. It is often credited with influencing Lyndon Johnson's decision to drop out of the race for President. "If I've lost Walter Cronkite ... [I]'ve lost Middle America", he stated. Under Cronkite, the newscast began what would eventually become an 18-year period of dominating the ratings among the network evening news programs.
CBS News from reports from the United Press, one of the three wire services that supplied newspapers with national and international news. In December 1930 CBS chief William S. Paley hired journalist Paul W. White away from United Press as CBS's news editor. Paley put the radio network's news operation at the same level as entertainment, and authorized White to interrupt programming if events warranted. Along with other networks, CBS chafed at the breaking news embargo imposed upon radio by the wire services, which prevented them from using bulletins until they first appeared in print. CBS disregarded an embargo when it broke