The situation is best served by both candidates being there. Senators not only vote, they engage in negotiation sessions behind close doors. If they are both there and sign on to any agreement no party can hang it around the other.
LLS
If Lieberman jumps to the GOP tonight, McCain will be the majority leader in the morning. That would mean the Republicans control the Senate and Reid is history. It would also mean if there were a 50/50 split on the vote, then Cheney would become the tie breaker. How about this one. If they all voted "present" then they would not be committed on record as voting yae or nay and off the hook. Again, wouldn't Cheney have to vote to kill or pass the bill? Talk about a situation.