[cnn-photo-caption image=http://i.l.cnn.net/cnn/2008/images/02/21/art.debate1.cnn.jpg caption="The stage is set for tonight's debate."]
AUSTIN, Texas (CNN) - The Democratic debate here in Austin, Texas begins in about 15 minutes. The questions remain secret and no one is quite sure what will happen tonight. But one thing is clear: Hillary Clinton has a much tougher task ahead of her than Barack Obama.
Clinton has got to be the candidate of change tonight - she needs to change the race. Obama has won 10 straight contests (11 if you count today's "global primary"), and the momentum is clearly on his side. The pressure is on the New York senator to have a defining moment that changes how voters view her – and how they view Obama.
But can she stop his momentum without harming herself? She clearly needs to draw distinctions with Obama and knock him off stride - without appearing overly negative. That’s because Obama thrives on her negativism - it boosts his argument that he is a different type of politician, the candidate that can change the highly-partisan tone of Washington.
Clinton also needs to get voters to see her in a different light. Bill Clinton has talked recently about his wife's ability to empower people - if she can convey this message tonight, she will likely be well-received. But it’s a tall order.
Obama's task, on the other hand, is easier. He merely needs to avoid a big slip up, and fend off anything Clinton throws at him with a smile while calling her out on her attacks.
He also needs to introduce himself to Texas' Latino electorate. Hispanic voters are expected to play a key role in the state's March 4 primary, and many here still don't really know who he is. They know the Clintons well - and the New York senator is banking on their support to carry her to victory.
But tonight's debate is co-sponsored by Univision, and will be broadcast in Spanish, giving many of these voters their first opportunity to get a long look at Obama. If they warm to him, Clinton is in trouble on March 4.
Let the debate begin!
–CNN Senior Political Analyst Bill Schneider