Howard Dean's famous first line to the DNC in California (IIRC) was (I'm paraphrasing) "I want to know why the Democrats are supporting Bush's war in Iraq." He got traction by hammering the other Democrats for being co-opted by the Republicans.
I love him for it. Whether or not he wins-- and he does still have a chance-- the Democratic candidates (apart from Lieberman) are all better for it.
If he does not win, though, and either Edwards or Kerry does, I think either of those candidates can use the point Dean's been making to their advantage in a wholly different way. "We tried to work with the president," they can say. "We tried to be bi-partisan, and we supported the president in a number of ways. But the president kept going back on his word: to provide adequate funding for No Child Left Behind and the AIDS-related aid package for Africa, to ensure solid post-war planning in Iraq. He has refused to work with us, he has put partisanship above results, and the American people are worse off for it."
Thanks to Dean and Bush, Edwards and Kerry are both in a good position to be seen as moderates. They should use this to their advantage by presenting themselves as men who tried to work with Bush and not simply against him in order to help the American people, but who have been frustrated by his partisan politics.
The candidates have already been doing this in a piece-meal fashion. Kerry, of course, defends his war vote in this fashion. I believe Gephardt (and/or Lieberman) has explained his NCLB vote as "the only way public education was going to get any funding under this president." That's exactly the right idea, politically speaking, in my opinion. But those points would be much stronger if they were put in the context of this over-arching theme. (One that, admittedly, may have to wait until the general election-- I doubt it'd help anyone win the primary.)
Whatever the actual reasons for their votes for NCLB, the Patriot Act, the Iraq War, and so on, Kerry and Edwards can use those votes to their advantage in the general election: they're bi-partisan moderates (they can say: remember, it's not the truth I'm after here) who want to get something done for the American people, and who will put results above politics.
PS. The dirty tricks described in the Globe today (http://www.boston.com/news/nation/articles/2004/01/22/infiltration_of_files_seen_as_extensive/) are exactly the kind of tactics these candidates could refer to to make their argument about the Republicans under Bush.