As Brad notes, Lieberman–Warner didn't come close to getting the 60 votes needed for cloture this year. It got 48 votes (roll call here), plus pledges from six more senators who missed the vote but say they would have voted for cloture. So that means it came up six votes short.
Where might those votes come from if a similar bill is brought up next year? Obviously, a whip count this far out is very, very rough, but here's some idea. Among the ten senators who missed the vote and didn't pledge to support cloture, there are two Democrats: West Virginia's Robert Byrd and North Dakota's Kent Conrad. Byrd apparently opposed the bill (although his fellow Mountain Stater, Jay Rockefeller, voted for cloture), so getting his vote seems unlikely. Conrad was apparently on the fence, and his home-state comrade, Byron Dorgan, voted no. Among the Republicans who didn't vote, only Pennsylvania's Arlen Specter seems like the type who might be persuaded to vote for cloture; perhaps Judd Gregg, who will face re-election in 2010 in environmentally conscious New Hampshire, is also a possibility.
If, say, two of those four end up supporting cloture, proponents of cap-and-trade would have to pick up four votes from the "no" group without losing any supporters (it's conceivable that someone like Norm Coleman or Elizabeth Dole might suddenly have a change of heart when they're not facing tough re-election fights). Wayne Allard of Colorado and Pete Domenici of New Mexico could well be replaced by the two Udalls. Then you'd have to either cobble together two more votes from among the four Democrats who voted no--Dorgan, Tim Johnson (S.D.), Mary Landrieu (La.), and Sherrod Brown (Ohio); win an upset victory over someone like Texas's John Cornyn or Mississippi's Roger Wicker; or pick up a stray Republican or two (probably by bribing them with pork).
All in all, it looks like it's going to be an uphill fight unless the occupant of the White House decides to expend some political capital on it. It probably also wouldn't hurt if gas prices went down in the interim, taking some of the emotional edge off the vote, but what are the odds of that?
--Josh Patashnik