The Command Post reports that the Dean campaign has "paused" its nationwide ads, in favor of a focus on New Hampshire. That sounds like a tacit recognition of the truth: if Dean comes in third or later in NH, he's done. The only thing he can do at that point is bring his big war-chest to bear as an enticement to sway the real nominee to give him a good position in the new government, should the party be successful in the general election. It's therefore important to conserve that resource.
If Dean manages second or, against the odds, wins in NH, he'll be back to his 50 state plan. As has been reported, Kerry has limited funding to campaign across the country. Edwards, who everyone agrees was really Iowa's big winner, has a different problem. South Carolina is the next big poll, yes; but even if he wins, there will then be eight more non-Southern states, including two more New England states, before any more of the South votes. Edwards has to make the argument that he is the most electable nominee stand in the face of those eight states' returns, which are not as likely to favor him as the South.
So, it's possible that Dean, if he can survive in NH, may likewise survive being brutalized in South Carolina to fight on through the eight states that follow. (Arizona, Delaware, Missouri, New Mexico, North Dakota, Oklahoma, Michigan, Washington State, and Maine, if you're keeping score.) The week after that, Tennessee and Virginia vote.
Since people are offering their reads on these things, I'd say Dean has to pull first or second in NH to stay in the game. If he's feeling bold, he might try to stick it out even with a third place finish, but the evidence suggests he's already making contingency plans to buy the influence he can't win through the electorate. Edwards can survive whatever comes in NH, but if he wins SC, and then the next week carries TN and VA, he can probably ignore the results in the eight states and win the nomination on the strength of the Super Tuesday vote. If he loses SC, TN, or VA, he's not likely to win the nomination. Still a long shot, but not nearly as long as he was.
As Mark Steyn reports, the Democratic party's political functionaries seem to have rallied behind Kerry. That may go a long way to undo his finance troubles. It may be Dean can buy him, too, which infusion would be all he likely needs. If he does carry NH strongly, I'd say a Dean purchase and Kerry as the nominee are most likely, but with Edwards not being out of it until after TN and VA vote--he could still win if the bulk of the party decides on the evidence that he can split the South in the general election.