Good write-up, Pat. As usual, you have distilled your extensive knowledge of history into a credible scenario for the current election. I personally fear that Obama will win and the nation will be saddled with 4 more years of Obama's agenda (if he has one). However, if the Republicans can take the Senate and hold the House, they can limit the damage he could do, even going so far as blocking any nominations to the federal courts of left-wing jurists.
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,"...
You two are dreaming. How long did it take for the Tea Party people to be co-opted into the system and vote to raise the debt ceiling? Less than 6 months.
The GOP hasn't changed a bit and is not going to change.