And so it begins

Slowly but surely, the superdelegates are abandoning Hillary Clinton. It's been a slow trickle, but Obama has gained a net 27 supers in the last two weeks, according to the Associated Press. "Given where the race is at right now, I think it's very important for us to play a role around bringing the party together around the candidate that people have chosen," says one former Clinton super.

That sentiment will spread very, very rapidly unless Hillary's "firewall" works. Presumably, if she loses either Texas or Ohio, she'll drop out (as Bill suggested). But suppose she wins both states by narrow margins -- perhaps edging Obama in the Texas popular vote but losing the delegate count -- and decides to press on despite still being way behind by every measure (pledged delegates, total delegates, popular vote, states won, etc.). If that happens, I think there's no way the superdelegates will let this thing go all the way to April 22 (when Pennsylvania votes). The trickle will become a flash flood, the numbers will become totally lopsided, and Hillary will be hounded out of the race very quickly. Worst case, Mississippi on March 11 (the last pre-PA primary) becomes Obama's final coronation, and Hillary concedes that night or the next day.

The only thing Hillary can do to stop the bleeding is win, and win big.

P.S. For Hillary, there's a big advantage to bowing out gracefully, of course: if Obama loses in November, she immediately becomes the prohibitive favorite for 2012 -- perhaps truly inevitable this time. (This creates an interesting situation on both sides of the aisle, with Clinton and Romney both at least half-rooting for their own party's candidate to lose, so they can get another shot in four years.)