Sumner Welles (1892-1961) was an American diplomat who helped create the good-neighbor policy with Latin America during the 1930s.

Sumner Welles was born in New York City on Oct. 14, 1892. He was educated at Groton School and graduated from Harvard in 1914. Entering the diplomatic service in 1915, he served as chargé d'affaires in Japan. In 1921 he was placed in charge of Latin American affairs in the U.S. State Department. During his short term he undertook a special mission for the department in the Dominican Republic, assisting in the reorganization of Dominican finances. From this assignment came his most important literary work, Naboth's Vineyard, still the best history of the area.

In 1933 Welles was appointed undersecretary of state in Franklin Roosevelt's administration, an appointment made easier by his earlier association with Roosevelt. His service in this post for more than a decade was the most distinguished part of his...