There's just too much going for the Democrats this year for the election not to remain eminently winnable no matter what happens (well, within reason) between here and the convention. Rather, the problem is that the party is losing a golden opportunity to try to put the race away early, the way Bill Clinton more or less did with Bob Dole in 1996 - by using their enormous fundraising advantage to rebrand John McCain as a Dole-style loser while he's still struggling to get his money-raising operation up to par.
The Clintons don't care. This is not about the interests of the Democratic party. It's all about them.