How on earth does one make sense of it? The last week, he has plunged from one gimmick to another, finally landing on this transparently cynical bid to "suspend" his campaign until a bailout deal - then returning to Washington to actually say nothing while the deal collapsed:

At the bipartisan White House meeting that Mr. McCain had called for a day earlier, he sat silently for more than 40 minutes, more observer than leader, and then offered only a vague sense of where he stood, said people in the meeting.

In rode the man on the white horse, whom no one really needed. And when he got there, he didn't resolve the impasse, and he didn't propose a plan. He just sat there, er, blinking. Now he's tied himself into the comic position that if this deal isn't made by tonight, he won't show up at the debate, so there.

It's like a seventeen year old going to their room and slamming the door when he can't be the center of attention. Matt Cooper notes:

McCain certainly hasn't helped and now we're at a point where a deal seems unlikely tomorrow in time for the debate which means McCain will have to make another decision--whether to swallow his pride and show up for the Meeting in Mississippi or be the biggest no-show in the history of American politics. Since he doesn't seem to have added anything to the negotiations in Washington, it's hard to see why on earth he should show up for the debate with Barack Obama.
If he shows up with no deal, he'll look beyond lame. If he shows up after the deal, he will not be able to say truthfully he had anything to do with it, especially if he now leads opposition to the bailout. All in all: it's very hard to know what is going on in his head, what stunt he's going to pull next, what new drama he wants to unveil. Calming, isn't it, to think what a McCain presidency would look like. Not boring, anyway.

(From Andrew Sullivan in the Atlantic