These turds ain't got the guts to go nuclear... lets call their bluff!
I expect Reid (and Hillary) will make this a party loyalty vote, with all sorts of dire reprisals agaianst any Dim who breaks ranks over Roberts. They'll have the full support and backing of MoveOn and the other leftist groups in making the "traitors'" lives miserable.
My fear is that the Dims won't even need to filibuster, that they'll be able to count on enough RINOs jumping the GOP ship to defeat the Roberts nomination on an up-an-down floor vote. Snowe and Specter are already slipping away, and that means they'll take Collins and Chafee with them for certain. And that leaves lots of room for mischief for the likes of Voinovich and Hagel. The Rats then get to have their cake and eat it too - they shoot down Roberts and keep the filibuster for another day.