Senate Majority Leader Harry M. Reid (D-Nev.) filed a motion Wednesday to begin the confirmation debate of defense secretary nominee Chuck Hagel, setting up a vote by Friday that would require 60 votes to cut off a potential filibuster by Republicans.

Democrats had been hoping to avoid needing a supermajority to clear the confirmation hurdles for Hagel, a former GOP senator from Nebraska whose centrist views on national security drew stern rebukes from his former Senate Republican colleagues during hearings before the Armed Services Committee last week.

Moreover, Hagel’s nomination has become ensnared in the fight by senior GOP hawks, led by Sens. John McCain (R-Ariz.) and Lindsey O. Graham (R-S.C.), to extract more information about the response to the Sept. 11 attack on the U.S. consulate in Benghazi, Libya.

Their latest request came in a letter this week asking President Obama to explain whether he ever asked the Libyan government for help during the eight-hour siege.

Reid lamented the unusual step of needing 60 votes to win confirmation of a Cabinet-level nominee. “What a shame, that’s the way it is,” he said.

Already counting on 55 votes from Democrats, Reid will need five Republican votes, and early indications are that they are very close or already over that mark.

A pair of GOP veterans, Sens. Thad Cochran (Miss.) and Mike Johanns (Neb.), have announced they will vote to confirm their former colleague, and several others indicated they would vote to end a filibuster.

The vote must be held by Friday, under Senate procedures. If Hagel clears the 60-vote mark, it is likely the chamber will then move to a full confirmation vote.