The larger point, however, is that whoever finally gets the Republican nomination will be a deeply flawed candidate. And these flaws won’t be an accident, the result of bad luck regarding who chose to make a run this time around; the fact that the party is committed to demonstrably false beliefs means that only fakers or the befuddled can get through the selection process.

Of course, given the terrible economic picture and the tendency of voters to blame whoever holds the White House for bad times, even a deeply flawed G.O.P. nominee might very well win the presidency. But then what?

The Washington Post quotes an unnamed Republican adviser who compared what happened to Mr. Cain, when he suddenly found himself leading in the polls, to the proverbial tale of the dog who had better not catch that car he’s chasing. “Something great and awful happened, the dog caught the car. And of course, dogs don’t know how to drive cars. So he had no idea what to do with it.”

The same metaphor, it seems to me, might apply to the G.O.P. pursuit of the White House next year.