James Fallows argues in The Atlantic that John McCain's self-deprecating appearance on Saturday Night Livethree days before the election indicates that he has, on some level, accepted the idea that he is probably going to lose:

For a candidate coming from behind, every second of the final week of the campaign is like a second in cardiac-surgery operating theater, with absolutely no room for fooling around or wasting time, money, or effort that could be used to sway that last crucial vote. (Think: the last days of Gore-Bush in 2000.)

For a candidate who thinks he's ahead, and might actually become president, inevitably there's a tone of new seriousness right at the end: What we've been working for years is within our grasp, let's not screw this up, and let's be sobered by how different the world is going to look in a few days.

John McCain on Saturday Night Live

UPDATE: Leslie Savan shares a similar view in her latest column for The Nation:

"Like Al Gore's famous hot tub appearance on SNL, which tipped us off to his decision not to run in 2004, McCain's que cera performance (evident elsewhere on the trail in these last few days) was almost an admission that he knew he was about to lose, padded out with every imaginable electoral excuse. Standing next to Fey's Palin, he presented a cheerier, more ironic version of the victimhood he's been pulsing with for months. "Barack Obama purchased airtime on three major networks," he said. "We, however, can only afford QVC." He went on to hawk kitsch like Joe the Plumber action figures, pork-cutting knives, and the "10 commemorative plates that celebrate the 10 townhall debates between Senator Obama and myself. They're blank, he wouldn't agree to those debates."