The likely Constitutional option – From the WashPost: “But the scenario most widely expected among senators in both parties is that he would seek a ruling from the chair -- Vice President Cheney, if it looked as if the vote was going to be close -- that filibustering judicial nominations is out of order.”

The Republicans would probably want to keep Cheney out of sight, if possible, to indicate that the Senate’s Constitutional option is separate from the disinterested executive branch. Maybe I’m extrapolating, but it appears from this passage that the WashPost believes the rules change is a done deal.