Wanted to add one thought to David's full-bodied analysis of tonight's Democratic results. If you run the numbers, Senator Clinton has almost no chance of catching Obama in the pledged delegate totals, even when you take her wins today into consideration. (Here's the proof.) In order to catch him in the delegate count, she needs to win by completely unprecedented margins in every state going forward. That's not bias. That's fact.
That means she can take her campaign in one of two directions: she can attack Obama so thoroughly that he becomes radioactive and no voters will touch him, or she can use some combination of superdelegates and Michigan/Florida to overrule the will of the people who have voted thus far. Either route creates huge problems for the party. Both damage Clinton even if she does come away with the nomination (because her primary win looks ill-begotten and gangster) and both destroy all of the goodwill and energy currently surrounding the Democratic Party.
I'm not saying Clinton should drop out. She can do as she pleases. But I am saying she should be aware of the consequences on her choices as she decides how to move forward. The difficulties she faces in climbing back into this thing, her wins today notwithstanding, are very real.