部分的核実験禁止条約
In January 1961, he was appointed Ambassador at Large in the Kennedy administration, a position he held until November, when he became Assistant Secretary of State for Far Eastern Affairs. In 1961, at the suggestion of Ambassador Charles W. Yost Harriman represented President Kennedy at the funeral of King Mohammed V of Morocco. During this period he advocated U.S. support of a neutral government in Laos and helped to negotiate the Partial Nuclear Test Ban Treaty in 1963.