Democratic aides in both the House and Senate are already distributing past quotes from leading Republicans about the impropriety of filibustering presidential cabinet nominees. One, from 2005, from Mitch McConnell: " I think the president is entitled to an up-or-down - that is simple majority - vote on nominations, both to his Cabinet and to the executive branch and also to the judiciary. The filibuster was not used for 200 years. The country did just fine."
So far only three Republicans have publicly committed to supporting cloture - the procedural motion to end the filibuster - on the Hagel nomination. They are Sens. Mike Johanns (R-NE), Susan Collins (R-ME), and Thad Cochran (R-MS). Sen. John McCain (R-AZ) was among their number but on Wednesday began to backtrack. Other Republicans have suggested that they'd also drop their filibuster threats provided they receive more information from the administration about the terrorist attack on a U.S. facility in Benghazi, Libya last year.
The support to confirm Hagel thus exists in principle, and his confirmation is by no means doomed. But it hasn't fully materialized in the 24 hours before the vote.