Hayes, Carlton J(oseph) H(untley) (1882–1964)

US historian and diplomat. He was one of the leading authorities on modern nationalism, writing about it in such works as Essays on Nationalism (1926) and Nationalism: A Religion (1960). He served as US ambassador to Spain (1942–45), with the express goal of dissuading Spain from assisting the Axis powers; he described this mission in the book Wartime Mission in Spain (1945).

Hayes was born in Afton, New York. He studied at Columbia University, gaining his PhD in 1909, and staying on as a professor (1910–50). A convert to Roman Catholicism (1924), he became a cofounder of the National Association of Christians and Jews and was its Catholic cochairman (1928–46). He was the author of a long-standard college history textbook, Political and Social History of Modern Europe (1916).