Weigel thinks it's a bad strategy:
All of this liberal discussion about challenging Barack Obama (it really is limited so far to Robert Kuttner, Michael Lerner, and a handful of other people) misses the point about how to effectively pressure a political party into doing what you want. The least effective way of pressuring the party is to back a stunt campaign against the president of the United States. Nothing gets more coverage. Nothing is less winnable.
Seriously: Lerner and Kuttner? I suspect they'd even get Mickey back on the Obama bus.