In both the 1952 and 1956 elections , Stevenson was defeated in landslides by Republican Dwight D. Eisenhower . He sought the Democratic presidential nomination for a third time at the 1960 Democratic National Convention , but was defeated by Senator John F. Kennedy of Massachusetts . After his election , President Kennedy appointed Stevenson as the United States Ambassador to the United Nations . He served from 1961 until his death . He died on July 14 , 1965 , from heart failure ( after a heart attack ) in London , following a United Nations conference in Switzerland . Following public memorial services in New York City , Washington , DC , and his childhood hometown of Bloomington , Illinois , he was buried in his family 's section in Bloomington 's Evergreen Cemetery
1960 Democratic National Convention
1960 Democratic National Convention
Adlai Stevenson II