From a New York Times article on the March 4th primaries in Texas and Ohio:
"She has to win both Ohio and Texas comfortably, or she's out," said one Democratic superdelegate who has endorsed Mrs. Clinton, and who spoke on condition of anonymity to share a candid assessment. "The campaign is starting to come to terms with that." Campaign advisers, also speaking privately in order to speak plainly, confirmed this view.
Several Clinton superdelegates, whose votes could help decide the nomination, also said Monday that they were wavering in the face of Mr. Obama's momentum after victories in Washington, Nebraska, Louisiana and Maine last weekend.
Polling puts Obama ahead by double digits in tomorrow's primaries in Virginia, Maryland and the District of Columbia. The next two - in Hawaii and Wisconsin - are also favorable for Obama. If he wins all those contests, Clinton will have to crush him in Ohio and Texas to remain viable. Otherwise, it's all over for her campaign. From the NYT article:
"They are looking way too much at Florida, Michigan and McCain, because all three won't matter if she doesn't blow Obama away in Texas and Ohio," said another Democrat who is both a Clinton superdelegate and major donor, and who spoke on condition of anonymity to offer a candid assessment of campaign strategy. "Obama has momentum that has to be stopped by March 4."
Maybe it will be decided before the convention. Because, even in a best case scenario for the Clinton camp, the Senator will not "blow Obama away." Best case, a narrow victory. If the rest of February goes well for Obama, even that's unlikely.