That's exactly why I think the Democrats will cave before we can use it on this nomination. If they are even remotely intelligent, they'll adopt the "live to fight another day" principle.
The problem is, that the longer they wait to run a filibuster, the worse their political problem the next time, on the next nominee.
Suppose, for example, Ginsberg or Stevens were to leave the Court, and The President were to replace that person with someone even as "moderate" as Kennedy --- that would really cook the liberal goose - yet could they filibuster such a candidate? (Suppose for purposes of this discussion, judicial philosophy of Gonzales...)
Their problem is right now... with this nomination ... the next one may be too late because even a moderate justice may well hose them.