We'll assume that Obama wins SC, Hillary wins Florida and Nevada is a toss-up. If so, neither candidate goes into Feb. 5 with a whole lot of momentum. As with the Republicans, it will be impossible for either Hillary or Obama to campaign effectively in all those states; however, both have sufficient money to run decent media campaigns in the more important races, whereas the Republicans are all so broke that, absent Romney writing himself a big check, they'll be relying on the free media for their publicity.
On Super Duper Tuesday, 22 states hold nominating contests on the Democratic side. Those states account for 2088 delegates--roughly 50% of the total at the August convention, although not all of them will be awarded on Feb. 5.
Unlike with the Republican candidates, however, there are very few states on the Democratic side where either Hillary or Obama has a distinct advantage. We assume that Hillary will comfortably carry New York (280) and New Jersey (127), and probably Connecticut (61). Obama will easily carry his homestate of Illinois (185). (Numbers in parentheses are the delegates allocated to the state.)
We also give Obama an edge in some southern states where African-American voters make up a disproportionate number of Democratic primary voters: Georgia (104) and Arkansas (47).
After that, it's a crapshoot. Edwards is a complete non-factor--he cannot do media and he can't possibly carry any state. Whether he can crack the 15% barrier to even get delegates is a question, but he's not likely to walk off with more than a couple dozen, at most.
The other complicating factor is that all the Democratic contests award delegates proportionately--there's no winner-take-all contests like on the GOP side. That means that even in New York, Hillary will have to cede some delegates to Obama, while Obama likewise will give up some delegates in Illinois to Hillary. That factor makes it difficult for either candidate to single out particular states for special attention.
In effect, the Democrats are hosting a national primary on February 5. But if it's close, say one candidate gets 45% of the vote and the other gets 40% (the rest going to Edwards and other forms of wasted votes), then their delegate totals at the end of the day are going to be very close. Edwards, if he can pick up enough delegates, could become a spoiler.
The other spoiler is the Democratic Super-Delegates--various elected and party officials who aren't bound by the primary/caucus votes.
Right now, we don't see February 5 being decisive for either Hillary or Obama, with one exception. Obama has a shot, at least, of running the table--SC, Nevada and Florida--before Feb. 5, which would give him sufficient momentum to score a big enough victory on Super Duper Tuesday to propel him, eventually, to the nomination. (The same would apply to Hillary is she ran the table, but we just don't see her winning SC).
As with the Republican side, we'll update this analysis after Saturday's contests in SC and Nevada and see if the picture is any clearer.