Updated: 10:53 p.m.

The Senate will wrap up work on President Barack Obama’s tax cut deal Wednesday and begin debate on the new Strategic Arms Reduction Treaty, punting an ugly fight over a one-year spending bill until Thursday night.

Although the Senate had been scheduled to vote on the tax bill at 12:30 a.m. Wednesday, Majority Leader Harry Reid (D-Nev.) and Republicans agreed Tuesday night to put off the vote until after noon Wednesday.

Under the agreement, the Senate will first hold three procedural votes on proposals by Sens. Tom Coburn (R-Okla.), Jim DeMint (R-S.C.) and Bernie Sanders (I-Vt.), although none is expected to succeed.

Obama’s tax cuts are expected to easily pass in the Senate, and the plan picked up a new, albeit reluctant, supporter Tuesday night. Sen. Sherrod Brown (D-Ohio) announced he would back the bill, despite voting against cloture Monday.

In a floor speech to a nearly empty chamber Tuesday night, Brown said he did not want middle-class tax cuts held up as a result of GOP demands that the expiring 2001 and 2003 cuts be extended for all income levels.

“I’m angry that Republican Senators insist on awarding bonus handouts to millionaires and billionaires. But I’d be more angry if we let them continue to play games with people’s livelihoods,” he said. “That’s why it’s with great reluctance that even though I opposed the cloture vote … that I will vote in favor of this bill.”

After the vote, Reid will begin work on the arms reduction treaty with Russia. Democrats now say that START has enough supporters to meet the 67-vote threshold to pass.

Reid had initially intended to begin work on the omnibus spending bill after the tax vote, but he is now pushing it off until late Thursday in the face of stiff GOP opposition. Republicans have threatened to filibuster the omnibus, and DeMint said Tuesday that he would force a reading of the bill on the floor, a process that could take 60 to 70 hours, a Reid aide said.

Reid could begin debate on the omnibus bill before Thursday, because Senate rules allow debate on the arms reduction treaty and the omnibus to occur simultaneously.

However, by delaying the omnibus debate until late Thursday, Reid appears to be trying to box Republican opponents into either voting for the measure Saturday, when the current continuing resolution funding the government will expire, or shut down the government by filibustering the bill.

Democratic aides said any GOP filibuster attempt would at most delay the spending bill. A senior Democratic aide familiar with the vote count said Reid had 66 votes for the measure as of Tuesday evening, enough to break any filibuster Republicans may try to muster.

Emily Pierce contributed to this report.