Do McCain, Biden, or Obama sit on any of the relevant committees or subcommittees at this point? I ask that sincerely, because if they do not, they really have no official input into the process at this point in time as Senators. If they do, then they should probably seek to provide that input now, when it counts. If not, I can't imagine what they could do to help right now, and their presence could possibly hurt and polarize the process either way.
-- Todd/Leviathn