Moreover, much as Reagan's loss to Jerry Ford led to his subsequent ascendancy, Sarah will either rise from her Vice-Presidency when McCain hangs it up after a single term -or- if they lose in a fortnight, she is the odds-on GOP favorite and, thereby, (give four years of Bama socialism ...) the next President.
So, there it is ....
Most presidents are two termers.
Who was the last losing vice president to ascend to the presidency in a later election?
FDR (lost in 1920 as VP candidate, won in 1932, wouldn’t leave office).
Recent losing VPs don’t get out of the primaries.