"Credibility gap" was first used in association with the Vietnam War in the New York Herald Tribune in March 1965, to describe then-president Lyndon Johnson's handling of the escalation of American involvement in the war.
The advent of the presence of television journalists allowed by the military to report and photograph events of the war within hours or days of their actual occurrence in an uncensored manner drove the discrepancy widely referred to as "the credibility gap." .