In 1936 Bunche authored a pamphlet titled "A World View of Race." In it Bunche wrote: "And so class will some day supplant race in world affairs. Race war will then be merely a side-show to the gigantic class war which will be waged in the big tent we call the world."
Bunche spent time during World War II in the Office of Strategic Services (the predecessor of the Central Intelligence Agency) before joining the State Department in 1943, where he became associate chief of the division of dependent area affairs under Alger Hiss. He became, with Hiss, one of the leaders of the Institute of Pacific Relations (IPR).
He participated in the preliminary planning for the United Nations at the San Francisco Charter Conference of 1945, and in 1946 he was a member of the first U.S. delegation to the U.N. He then became an employee of the U.N.