From 1957 to 1961 , he worked as an assistant in the Department of State .
From 1953 to 1955 , he was an economic officer in Addis Ababa , Ethiopia , and a political officer in Mexico City from 1955 to 1957 .
From 1957 to 1961 , officer worked as an assistant in the Department of State .
From 1953 to 1955 , he was an economic officer in Addis Ababa , Ethiopia , and a political officer in Mexico City from 1955 to 1957 .