Jay Cost  makes a very important point at RCP today...something I've said but not set out nearly so well...that being that Hillary, despite Obamamania, still has a good shot at the Democrat nomination. How? One word. Delegates. It's all about winning a majority of delegates to your convention, (in the Dems case a little over 2,000).
A few important things to keep in mind about the Democrat's process. One, it's proportional, (meaning you get a number of delegates from each state according to your percentage of the vote in that state - unlike the GOP's usual winner-take-all format). This means that, even if you're losing, your still adding delegates to your total. Second, the Democrats have about 800 unpledged "super-delegates", (national committee members and elected officials), who can wait until the convention to decide whom to support.
When you add those facts with the reality of her support within the Democrat party's infrastructure, (much more widespread than Obama's), it's absolutely crazy to suggest that she's done, even if she fails to come in first in a single state prior to super-duper Tuesday.
Don't get me wrong. I'm not saying she'll be the nominee. Despite her big early lead, (and current national lead), I've felt, and still do, that the Democrats are too sane to commit collective political suicide. As Bill Clinton once said about party nominations, "Democrats fall in love, Republicans fall in line". Well, the problem for him (and his wife) is that the Democrats ARE falling in love - just not with Hillary.