Vance served as senior adviser to the secretary of state, coordinator for international narcotics matters, and executive director of the President's Cabinet Committee on International Narcotics Control (1974–1977).
As a high-ranking official, Vance served as a senior advisor to the secretary of state, coordinating international efforts against narcotics trafficking. He also headed the President's Cabinet Committee on International Narcotics Control from 1974 to 1977.