Senate Majority Leader Harry Reid cast doubt Wednesday on whether he will be able to muster the votes for a five-month extension of unemployment benefits, saying he is still one vote shy of a filibuster-proof majority.

The Nevada Democrat also noted that he does not yet have the votes to pass a major financial regulation overhaul, but he said that he would have had to wait until after the July Fourth recess anyway to press the bill.

Reid is largely having trouble getting the 60 votes needed to beat back a filibuster because of the death of Democratic Sen. Robert Byrd (W.Va.) earlier this week. Aides speculated that the Senate may not pass either bill until West Virginia Gov. Joe Manchin (D) announces a replacement. Reid said Wednesday, “I think he’ll do that quickly.”

“We’ll have to wait and see what a couple of Republicans do,” Reid told reporters of the expected Thursday evening unemployment benefits extension vote. “I would have 60 votes if Sen. Byrd were here.”

Republicans have repeatedly blocked attempts to extend jobless benefits in a larger tax extenders bill because the additional payments are not offset with spending reductions elsewhere. Sen. Ben Nelson (Neb.) has been the lone Democrat to side with Republicans on the issue.

The Senate’s Thursday evening vote will be an attempt to break a GOP filibuster of a narrower unemployment measure, which includes an extension of the first-time homebuyers’ tax credit, but not other tax extenders. The jobless benefits are not offset.

Sen. Susan Collins (R-Maine), however, declared her support for both the unemployment bill and the financial reform measure Wednesday. Fellow Maine Republican Sen. Olympia Snowe is also expected to support both but has not announced her decision yet. A third Republican, Massachusetts Sen. Scott Brown, said Wednesday he wants to review the financial regulation bill over the July Fourth recess, and he has not committed to voting for the unemployment bill yet.

Brown’s support for unemployment benefits would likely give Reid the 60 votes he needs.

However, Brown alone would likely not get Senate Democrats the votes they need to pass the financial regulatory reform bill.

Sen. Maria Cantwell (D-Wash.), who opposed the Senate financial reform measure, said she is still reviewing the conference report and refused to commit her vote. Cantwell or Byrd’s replacement will be needed to reach the 60-vote threshold.

Another potential GOP swing vote, Sen. George Voinovich (Ohio), said Wednesday he would oppose the unemployment bill and the financial regulatory measure.