When Wendell Willkie withdrew from the race for the 1944 Republican Party presidential primaries on April 5 , following his complete loss of the Wisconsin primary in which New York Governor Thomas E. Dewey , Harold Stassen , and General Douglas MacArthur claimed all the delegates , Associated Press , Willkie Admits Defeat , Quits Campaign , The San Bernardino Daily Sun , San Bernardino , California , Thursday 6 April 1944 , Volume 50 , page 1 .