One of the key issues for the subplot evolving in the race to be the anti-Kerry between Clark and Edwards is going to center on "character and integrity." Both men are contesting the nomination in Tennessee and Virginia, southern states where people put a premium on not just what someone does but on who they are.
I expect that Edwards campaign will be raising issues about Clark bringing forth the Shelton remarks (the Dean campaign has been using a retired general to recycle Shelton's charge). However, Edwards has problems of his own on this front. His campaign is basically being underwritten by the big litigation firms in California with $2000 checks from administrative assistants who are bankrupt and their spouses who have never even voted before. Apparently, the DOJ is investigating. (How nice of Ashcroft to undertake a politically motivated investigation just in time for the primary season while ignoring Bush's own widely reported bundling).
In the end, the character and integrity issue is more about perception than reality (how can we voters ever know enough about the candidates to make an informed judgement on character). In terms of perception I think Clark will do better on this front than Edwards. But the south also cares about whether someone is a good guy or not. I think Edwards connects with people in ways Clark doesn't. It will be interesting to see how this all plays out.