As usual, the Democratic Party would rather lose than not have everything they've ever wanted in a candidate. Republicans get up earlier, are better at messaging, controlling the debate and the media, and know how to compromise. Which is why they have a strong independent candidate in John McCain, who will be tough for any opponent to defeat.
Meanwhile, the Democrats, long after Obama was the inevitable nominee, continued to vote for Hillary Clinton instead of rallying around the winner and shoring up his chances for the general. If the party members themselves are this disgruntled about their nominee, then how are they to win over independents and Republicans over the next five months?
Nope, a majority of Hillary Clinton supporters would rather, they say, vote for McCain than their second choice, who is just as good on every issue (if not better, especially if we're talking about Iraq) except for healthcare. Are they mad at some perceived injustice perpetuated by the Obama campaign? If not, there's really no reason to dislike the guy and not vote for him. He campaigned hard and well, and avoided sexist or other nasty attacks. So, why doesn't he deserve your vote?