Why Edwards doesn't have to withdraw

Josh Marshall says the question is not why John Edwards should withdraw, it's why he has to.

In a post on Talking Points Memo, the liberal blogger writes that as long as the former North Carolina senator has enough money to spend and wants to run, he should:

First, as others have noted, his campaign has had an effect on this race out of proportion to his poll support in as much as he's forced the two other leading candidates to grapple with issues they would not have otherwise. And in this race specifically, there is at least a chance we could come into the convention with neither candidate having a majority of the delegates, in which case he might play the kingmaker. Not likely, but not impossible.

Marshall also says he does not know whether an Edwards withdrawal would help Barack Obama or Hillary Clinton more.