At the above link is an article from the LA Times about why Hillary's campaign is failing. I think that they need to go a little further back, and they will find that the real reason is the power of the activists on the Democratic side.
Last summer, Hillary was the presumptive nominee. She had the name, the Clinton machine, and lets face it, no real challenger. As a result, she started to run a general election sort of campaign, where she tacked right. What she failed to appreciate was the charm and charisma of the junior Senator from Illinois.
Since Hillary was taking a more moderate approach, she quickly became vulnerable to those on the Left whose only issue was to end the war. Popular and easy to explain, even though the reality is that it is extremely complex and the consequences are not easy to understand or predict, the issue was used by Obama to beat the heck out of her for her vote in support of going to war. At first, she refused to apologize, (what horror), but by January, she had to renounce for the first time her vote. Blaming it on Bush seemed to be the right move, since in the Democratic circles, Bush is the source of all evil.
But then she started to run on her "experience." This opened the door to attacks on her judgment, when coupled with her grudging acknowledgment that Bush fooled her, and her message becomes not only muddled, but vulnerable.
Once Hillary lost Iowa, her aura of invincibility faded quickly, to the point where she has lost the last 11 contests in a row. Amazingly, at least according to CNN, she is only around 100 delegates short of Obama.
Hillary is complaining that none of the media are treating Obama the same as she is being treated. I even heard some of the Sunday talking heads say that it is sexism. I don't think that it is, rather, I think that this is the normal level of inquisition that the press uses on Republicans. (Think about the coverage of Obama's supposed denouncement of Farrakhan versus Trent Lott or "Maccacca Allen).
The only hope that I see right now for Hillary is that the media are starting to take a more objective look at this "nice young man" and are finding problems. Like the last debate in which they are falling all over themselves to drop out of NAFTA, despite the damage it would do to the economy as a whole.
The only problem with waiting, is that Ohio and Texas are tomorrow. If Hillary loses both, she will probably be expected to drop out. Just about the same time that Obama starts to implode.
Gotta hand it to the Democrats - They have that circular firing squad down to a science.