Chris Wallace in Politico.com:
So far, Wallace has interviewed Sens. Hillary Rodham Clinton, Joe Biden and Chris Dodd and New Mexico Gov. Bill Richardson; both Sen. Barack Obama and former North Carolina Sen. Edwards have declined.
The Edwards campaign confirmed that the candidate declined but did not elaborate further. The Obama campaign did not respond to requests seeking comment.
Aside from his hourlong Sunday show, the Democratic candidates will not participate in any Fox News-sponsored debates, leaving Wallace to moderate three Republican contests over the course of 2007.