The correct answer is "the retreat of the US forces from Vietnam".
Walter Cronkite was an American Journalist who worked for CBS during the years of the Vietnam War. Upon his trip to the war zone in 1868, he was invited to dine with US Army General Creighton Abrams, who allegedly told him that it was extremely difficult to win the War in Vietnam.
Upon his return, Cronkite wrote an editorial in which, convinced by what General Creighton Abrams told him, expressed an overall reluctant opinion towards the country's efforts in the war.