Robert J. McCloskey, 74, former ambassador and State Department spokesman. McCloskey was a key briefing officer at the State Department. In June 1965, McCloskey confirmed that President Lyndon B. Johnson had authorized Gen. William C. Westmoreland to give any combat support requested by South Vietnamese forces. Johnson was angry over publication of the news, and the White House denied that that authorization had been given. Secretary of State Dean Rusk saved McCloskey’s job and appointed him deputy assistant secretary the next year. He was named ambassador to Cyprus in 1973. He also served as ambassador to the Netherlands and Greece. McCloskey retired in 1981 and later was ombudsman of the Washington Post for two years. On Thursday of leukemia in Washington.