Steve Perry offers this analysis, which seems esentially correct to me. (For further analysis along these lines, see my earlier post today -- "Day After Thoughts on Kerry and Dean"-- and the excellent comments it generated.)
... This is a huge win for Kerry, as much for the way the rest of the field broke as for his own point total. To put it another way, Kerry didn't just win; everybody else lost. No one is going to buy a resurgent Dean at this point. When all the spin's been spun, he still blew a 20-plus point lead in the state where his campaign first caught fire. John Edwards made relatively paltry gains on the basis of his strong Iowa showing, winding up a nose behind Wesley Clark, who skipped Iowa to engineer a strong showing in New Hampshire. (As of this morning, with 98 percent of precincts and over 200,000 ballots counted, Clark led Edwards by fewer than 700 votes.)
Consequently, there is no number two in the race at the moment. (And Kerry's fundraising is starting to reflect that: reportedly he raked in a million on the net this past week.) Edwards and Clark will tussle head-on for that designation starting next Tuesday, but if Kerry takes next week's big prize, Missouri--and with Gephardt's endorsement, it shouldn't be very close--and performs respectably elsewhere, the two Southerners may be running for vice-president at this point. That race is presumably Edwards's to lose, since Clark's military credentials would be redundant on a ticket headed by Kerry. ...