I don't expect much tonight. The format works for Palin and Biden is an old pro.
For Palin
I expect that, freed from the follow-up questions to her non-answers, she will expound on her talking points. Some might come away saying she seemed almost credible. In previous debates, she has shown an ability to cross-over from tough question to a more comfortable talking point. Former AK Governor Tony Knowles pointedly tells how Palin was asked about health care in small communities, and turned it into a talking point about revenues and budgets.
Palin will also attack. It seems that she enjoys the competitive aspect of the attack message, and I admire her ability to do it in a very folksy manner. She will probably use every opportunity she has to paint Obama/Biden as out of touch senators compared to the change that she and McCain will bring to Washington. They probably expect Biden to try to ignore her, so look for Palin to launch attacks against Biden in an attempt to get him to engage her in an ad hoc and unprepared manner.
Finally, I think Palin will shore up some weakening conservative infrastructure tonight. In fact, as I write this, I think this will be her most important task. For the most part, she has lost the intellectual conservatives and I don't think she gets them back. But she can plug the hole with a credible performance - meaning no Couric/Gibson interview type gaffes - and provide a little red meat to her keyboarding and airwave supporters. This is a pretty low bar to hurdle and I expect her to do well.
For Biden
Not too much here either. The best thing Biden can do, in my mind, is look presidential. That alone, as he stands on stage with Gov Palin, is worth more than any attack he can levy on either Palin or McCain. Be a man of few, strong words, and re-affirm what the Obama/Biden ticket means for average Americans.
Biden needs to talk his working-class language. Whether that is loaded with Catholic code words or not does not matter. His mission tonight is not to attack, even when engaged, but to stay on message. If we see Biden stray from message discipline tonight, it could be a problem.
Biden must be planning to ignore Palin. He must know that they know this and are creating ways for her to engage him on a personal level. He will need to control his temper and moderate his tone. Passion is good when promoting what you stand for, bad when defending your positions.
My final take: Draw. Both candidates will do what they need to do. Advantage: Obama. McCain needs a game-changer, not a draw.
One other consideration. The House votes on the "Recovery" legislation tomorrow (a little disappointed to see that the Dems are going to play the Orwellian name game). If the debate goes horribly awry for Biden tonight (unlikely), or if Palin performs much better than expected (more likely given the low ceiling of expectations), look for a little drama in the House as the Democrats flash something shiny in front of the media to distract them from the debate.