Obama, Clinton and the long hard slog

John King at CNN just used his magic delegate board to show that neither Hillary Clinton nor Barack Obama has any chance of winning a majority of delegates at this point - mathematical proof that superdelegates will decide this election. The only question is, what will sway them?

Money? Momentum? Fatigue?

Probably all of them. But only time, and tonight's results, will tell.

As of 5:11 p.m. PST, Obama has won Vermont, Clinton looks solid in Ohio, and Texas is a jump ball. Rhode Island is expected to go to Clinton, but no results are in.

National Journal's The Hotline has given us one of the inevitable story lines for tomorrow (unless Obama can pull it off in Ohio): Going negative works.

Prepare for a long and ugly brawl on the road to Pennsylvania.