"Dewey Defeats ___," infamous Chicago Tribune headline of 1948 (6)
I believe the answer is:
truman
(Other definitions for truman that I've seen before include "US postwar president" , "Harry S ...... was USA president 1945-53" , "33rd president of the United States, d. 1972" , "Harry S ... former US president" , "US president, 1945-53" .)