This article comes as close as I've seen to nailing the primary reason that the Democrat's fillibuster in the Senate needs to be ended now, and at least before there is a vacancy on the Supreme Court. The article notes that because of the Chief Justice's looming and expected retirement, the fillibuster of a SCOTUS nominee could be in the offing. "Mark Tushnet, a professor at Georgetown University Law Center in Washington, said Democrats" won't likely fillibuster Rehnquist's successor because it wouldn't tip the balance of the court, though of course they will oppose whoever is nominated.
I disagree. The lefty pressure groups like People for the American Way, NOW and NARAL, MoveOn.org, and American United For Separation of Church and State will all want the nominee to be fillibustered. So far they've had their way with Senate Democrats supporting fillibusters. The question on a SCOTUS nominee would be whether or not the Senate Dems could resist the pressure to fillibuster. I don't think they have it in them.
That the Senate Dems would probably fillibuster a SCOTUS nominee, provides another explanation of why they were so eager to "compromise" with the GOP on the appellate court nominees last week. All of their proposals left open the option of fillibustering future nominees to any appellate court, including the Supreme Court.
For this reason, it is imperative that the Senate GOP, led by Bill Frist, exercise the nuclear or nucular or constitutional or Byrd option and end the fillibustering of judicial nominees now. Anything less will lead to a SCOTUS nominee being fillibustered, and that would be disasterous for the GOP. We put you in charge to run the country because we don't trust Democrats to do that. Failure to do so will lead to your demise. As I said before, why bother voting to put the GOP in charge if they let the minority Dems tell them what to do.