Steve Benen nails it:
...the problem is hardly ever with what Hillary Clinton herself says. She’s sharp, on-message, and disciplined, rarely making the kind of verbal gaffe that hurts her campaign. It’s her surrogates that are the problem.
Absolutely right. I believe that people part ways with Senator Clinton when it comes to content. Yes, she's sharp, on-message and disciplined, but when she's all those things while defending her Iraq vote or attacking Senator Obama's oratory, voters run to Obama. They run especially fast when a Clinton surrogate says something idiotic.