Walter Cronkite, 1916 - 2009
Cronkite's report from Vietnam in 1968 is famous. He concluded the war was lost. What isn't well known is that prior to that trip, Cronkite was very much a traditional hawk on Vietnam. So, when he "went over" to the anti-war viewpoint, he did so with great credibility. As it was, after his Vietnam report was broadcast, the war was to last another five years.