Showdown in the Senate

Debate has begun on the nomination of Priscilla Owen to the 5th Circuit Court of Appeals. Senate Democrats plan to filibuster the nomination. Republicans do not have the votes to pass a cloture motion to end debate. The next step would be the nuclear option: a motion that would require only 51 votes to change the rules for ending debate. The Washington Post sums up the parliamentary sticking point the Republicans face:

To get there, Republicans will have to evade a requirement that they have a two-thirds vote -- 67 of 100 senators -- to change the chamber's rules.

Neither side has a firm count on how that vote would go:

Three Republicans have stated that they will oppose the change: Sens. John McCain (Ariz.), Lincoln D. Chafee (R.I.) and Olympia J. Snowe (Maine). Democrats, led by Minority Leader Harry M. Reid (Nev.), have expressed confidence this week that they will be able to attract three other GOP senators, with most of the focus on Sens. John W. Warner (Va.), Susan Collins (Maine) and Arlen Specter (Pa.).
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The Republicans plan one cloture vote, with the ostensible purpose of trying to shut off debate but the real intention of demonstrating that the nominee has majority support. Sometime after that, Frist is expected to seek a point of order designed to call the debate to a halt, with the presiding officer, probably Cheney, ruling in Frist's favor. Democrats would then appeal the ruling, and Republicans would counter with a motion to table the appeal. Whoever has a majority will prevail.

Senators on both sides of the aisle are seeking a deal to prevent use of the nuclear option according to the NYT:

Aside from Mr. McCain, the Republicans seeking a deal include Lincoln Chafee of Rhode Island, Olympia J. Snowe of Maine, John W. Warner of Virginia and Arlen Specter of Pennsylvania, chairman of the Senate Judiciary Committee. Among the Democrats, aside from Mr. Lieberman, are Ben Nelson of Nebraska and Mark Pryor of Arkansas.
Broadly speaking, the talks revolve around a potential deal in which a handful of Democrats would agree not to cooperate with their party's filibusters of some of the nominees, and a handful of Republicans would agree to vote against the rules change, at least for now.

All of this could take a week or more, which is why the White House wants the Senate to confirm John Bolton before the showdown on judicial nominations according to The Hill:

A split has opened between the White House and Senate Majority Leader Bill Frist (R-Tenn.) over the timing of the “nuclear option.”
The Bush administration would prefer the Senate to deal with the nomination of John Bolton to be U.N. ambassador before it gets down to the issue of filibustered judicial nominations.