Both the 20th and 21st centuries have seen failed presidencies.
William Howard Taft lost in 1912, though he might have retained office had not his old friend and former leader Theodore Roosevelt run as a third party Bull Moose candidate and won more votes than Taft.
Herbert Hoover failed through no fault of his own. The Crash of 1929 and the Great Depression were beyond his control, and every remedy he tried failed adequately to work.
Had the popular Cal Coolidge sought a second full term in 1928 instead of declaring, "I do not choose to run,"...