The reporters on the scene -- Dave Weigel today, Josh Rogin yesterday, and others -- believe a filibuster is unlikely in the Chuck Hagel nomination; they believe that if a simple majority support Hagel, he'll be confirmed. By this standard, Hagel is pretty safe; not a single Democrat has announced opposition, there's one Republican (Thad Cochran) supporting him, and so Hagel only needs to hold all but six of the unannounced Democrats. Barring anything new happening, that appears pretty much certain.
Indeed, the reporting has been that way from the beginning; once key Democrats agreed to support him, reporters (at least those I've read) have assumed Hagel was a lock.
I have no inside information at all; all I know is what's been reported. But I've been assuming the opposite all the way that it would take 60 votes, which means that Hagel is going to need at least five Republicans.
Basically, it comes down to how to interpret nominations in the last two Congresses. Weigel, Rogin, and others are treating simple majority as the normal process for cabinet selections, so that the GOP would be doing something extraordinary if it used the filibuster. Weigel notes, "If Republicans can hold 41 of their 45 members and oppose Hagel, theoretically, they can block him. But there's very little precedent for that, and Democrats may already have 57 votes."
But is it true that there's very little precedent for requiring 60 votes for a cabinet selection? It's true that Republicans didn't force a cloture vote for any of Barack Obama's choices in 2009, but it's also true that all of them cleared 60 votes; the closest was Tim Geithner, who was confirmed 60-34 with three Democrats missing the vote. Forcing a cloture vote in those cases would have been a purely symbolic act, so the fact that there was no cloture vote tells us more about Republican communications strategy than it does about GOP willingness to filibuster nominations they oppose.
Again that, we have plenty of examples of Republicans requiring 60 votes for both (other) nominations and legislation, and almost no examples in which fewer a nomination was confirmed with fewer than 60 (just going from memory, I believe there were none in the 111th Congress and perhaps two in the 112th Congress).
Indeed, I think it's more accurate to say that every one of Obama's cabinet selections was subjected to a filibuster -- they needed 60 votes -- than to say that none of them were. But I will say that we're in the realm of interpretation here.
Remember: cloture votes are simply not a perfect measure of filibusters. They're really not even a very good measure.
It's possible that Republicans in fact simply want to oppose Hagel, but for whatever reason don't want to defeat him. It's also possible that Hagel will have 60 votes, and that if he has 60 Republicans will not want a cloture vote.
It's also possible that Republicans really do oppose him and would like to defeat him, but they consider the use of the filibuster to be an extraordinary move, and don't actually oppose Hagel enough to do it. It's possible. But I find it very unlikely that any of them feel that way, and almost certain that most of them do not. I can imagine a cloture vote that passes with a handful of "no" votes on final confirmation peeling off and supporting cloture...I suppose I can even imagine a scenario in which the Republican conference sees that result coming and backs off of requiring a filibuster vote. But I think those stories are unlikely.
I guess we'll see. But if we do get confirmation by fewer than 60 votes, I'm going to be heavily inclined to believe it was because they didn't have the votes (because of a handful of cloture/don't confirm Senators) or that they wanted to oppose but confirm, and not because they really think that 60 should only be used in rare cases.