This argument of Conn's is the same dodge that the conservatives have been trying to run with George Bush ever since he became unpopular. Talk about messiahs! George Bush was their messiah for as long as his poll numbers were high -- or at least as long as he was winning elections. Now that he's unpopular, his unpopularity just goes to prove that he was never a real conservative (as proved by the very initiatives he proposed or passed while he was conservative messiah).
At the current time, a hard line conservative (one who didn't at least make the centrist noises that McCain sometimes does) would have done worse than McCain in the general election, as proved repeatedly by polling. It's a little ridiculous to say that if McCain fails it doesn't show something about the popularity of conservatism at the moment, when a more conservative candidate would have done worse.
I also find it funny that Conn is counting on Bush's sad-sack economy and Bush's stupid unplanned war to foul the nest for Obama so that we can go back to another Bush. It's unfortunate that this is entirely possible.