Conservatives were extremely nervous to learn that newly reelected Senator Specter (moderate to liberal Republican) would likely be chairing the Judiciary Committee.  Given his pro-choice position and his stance against judges who would come in ready to overturn Roe v. Wade, the GOP needed to pursue a method of neutering Specter if he were to refuse to report nominations out of the Judiciary Committee.

When Clinton was in the White House, the Republican Majority hid behind "the nomination hadn't be reported out and/or the Committee hadn't held hearings yet"  During W's reign, the Republicans were frustrated by nominations that couldn't come to a floor vote (due to filibusters).  

The problem isn't filibusters.  Republicans are fairly sure they might get 60 votes on most nominees (face facts, by and large, they will.)  The problem is that without Chairman Hatch reporting nominations out of Commitee, the Republicans need a means to fight anyone who opposes them.  This means wresting control of judicial nominations from the Judiciary Committee and its Chairman.  

It wouldn't happen all the time, but whenever the Religious Right and Ultra-conservatives have a nominee that could only muster 51 or 52 votes, they're going to want the means to confirm judges without the media circus that defines nominations these days.  "Quick and quiet before any realizes what just happened."  Specter won't report out a nominee or refuses to schedule hearings, call it a filibuster and quote the new rule "filibusters are out of order on judicial nominees".   The nuclear option allows Senators to ask for a floor vote once they have 51 votes.  

If you really want to defeat the nuclear option (I don't --- see my most recent post), call Specter's office and tell him "You've waited 24 years to Chair this Committee and now the ultra-conservatives want to take away your authority to review judicial nominees"  His number is 202-224-4254.  Oh, he's had a myriad of health problems (Hodgekins, brain cancer, etc.) so don't reminder his party's right wing is trying to castrate him now that he's the Cock of the Walk.