In addition to all the other reasons why Obama’s “hope and unity” theme doesn’t work is that he is framing his opposition to Clinton in these terms:

I believe that she is part of the fierce political battles that we had in the 90’s and that some of that carries over to today.

Now that he has actually started directly criticising Clinton and even using her name (audacious!), he is trying to use the “fierce political battles” of the ’90s as a way of saying that Clinton will have a hard time winning a general election.  Yet what I imagine many Democrats remember about the ’90s and those “fierce political battles” is that they won a lot of those battles and had the White House for eight years, and they probably also remember that they enjoyed the ’90s a lot more.  Also, they might prefer some “fierce political battles” to what many Democratic voters have seen as the repeated, craven capitulations of their side to the GOP.  To the ears of the average Democrat, more talk of cooperation and bringing the country together, while all very high-minded and pleasant in its way, is just another invitation to be dominated.  (Even though this had little or nothing to do with who was in the White House, it must be tempting for many Democrats to look back on that period as a relatively good one that they would like to repeat, much as some Republicans seem to want to live forever in the mid-’80s.)  Obviously, if you look too closely and remember who was involved in the biggest policy debacle of those eight years (that would be Hillary), memories of the ’90s don’t help Clinton as much as they might otherwise, but the power of nostalgia can have a significant effect. 

What is so remarkable about Clinton’s overwhelming lead thus far is that many progressives can’t stand her for policy and ideological reasons, but the hunger for victory is so great that many Democratic voters seem willing to back the establishment favourite with the most effective political machine.  Clinton has been compared to Nixon more than a few times, and this seems as badly wrong as you can go, but the dynamic today is very similar to the one we saw with Bush and conservatives in 1999-2000.  In both cases, there are core constituencies who distrust a candidate but swallow their objections for the sake of party unity and the desire to throw out the other side.  If Republicans and the Bush family in particular saw 2000 as a kind of payback for 1992, my guess is that a sufficiently large number of Democrats (and the Clintons themselves) see ’08 as their payback for 2000.  It seems that the mood of the Democratic Party is that of people who want some payback. 

Ironically, it is Obama who is effectively using the same kind of “I’m a uniter” rhetoric from Bush’s 2000 campaign that Bush used to make a claim that he was a different kind of Republican.  However, Obama is not the establishment’s favourite and also does not bring a political machine that has been involved in at least two successful presidential elections (which is what Bush ’00 and Clinton ’08 have in common), and so cannot combine the “change” rhetoric he likes so much with the reputation for specifically political competence in fighting elections.  Forget the arguments over “experience” in government for a moment, and consider simply the two candidates’ political experience, which is really something else all together.  Plenty of voters might be willing to accept his argument that experience in Washington is the problem, not the solution, but the Democratic voters who want to win don’t want to nominate someone who brings so little experience in drag-out electoral fights to the ticket.  Clinton doesn’t need to advertise her willingness to engage in political fights, since everyone knows she is very willing, and can delegate her attacks to all those people in her machine whom we know only too well.  Obama has no record of being able to engage in “fierce political battles” if that should become necessary, and so it is odd that he would make a point of drawing attention to what is, in fact, one of his most glaring weaknesses with the Democratic primary electorate.