Every prognosticator I’ve seen agrees that neither Barack Obama nor Hillary Clinton is going to roll up a big delegate advantage today. Both candidates will emerge with about the same mathematical chance to win the nomination as they had before the people went to vote. For that reason, the real battle today is psychological, and that means that spin is probably more important than reality. Part of winning the media battle is setting expectations so that you can meet or exceed them. I think both candidates have done a fair job on this front. Obama has succeeded in getting the media to cover Super Tuesday as more of a delgate-winning than a state-winning contest. Clinton has succeeded in preparing the media for a split decision. The perceived winner tonight, if there is one, will succeed by winning certain states.

If Obama wins California and several other states, he will definitely be cast as the winner. For Obama to get a landslide win he needs to be victorious in California and Missouri, and then either Connecticut or New Jersey. Zogby has Obama up 13% in California and up 3% in Missouri, but SurveyUSA has Obama down 10% in California and down 11% in Missouri. It’s too close to call.

Clinton will be able to claim a victory if she holds on in California, Missouri, New Jersey, and Connecticut. She’ll be able to lay claim to a resounding victory is she wins, in addition, Alabama and Tennessee, and big caucus states like Minnesota.

Those are the keys contests. If Obama wins the spin cycle he will probably be unstoppable. He outraised Clinton 30 million to 13 million in January and he will continue to outraise her going forward because so many Clinton supporters have already donated the maximum legal amount. With momentum, money, and media adoration, and a favorable slew of upcoming state contests, Obama would likely cruise to victory even if he didn’t win a (non-superdelegate) majority of delegates.

If Clinton wins the spin cycle, Obama will fight on, but weakened, tarnished, and desperate to start winning almost all of the remaining contests. That’s what is at stake.