Formal debate over President Barack Obama’s tax cut deal with Republicans will likely start in the Senate, although it remains unclear when Majority Leader Harry Reid (D-Nev.) will bring a bill to the floor.

Senior Democratic aides predicted Tuesday that while members of the Conference remain unhappy with the agreement, the Senate is closer to being able to pass the bill at this point even if liberals slow the process with a filibuster.

Although the timing of the debate is unclear, aides have said that assuming Sen. Bernie Sanders (I-Vt.) makes good on his threats of a filibuster, it could take three or more days to complete work on the Senate version. That could give the White House and House leaders enough time to round up enough votes for the deal, which extends all the President George W. Bush-era tax cuts for two years.

Senate Democrats entered a closed-door meeting with Vice President Joseph Biden on Tuesday still seething over the agreement, which many of them view as an unfair capitulation.

“Its very troubling thinking about borrowing $46 billion … to give it in tax cuts to people who are making more than $1 million in income,” Sen. Mary Landrieu (D-La.) said.

“I don’t understand why they’re doing it,” she added.

Landrieu also warned that even if she ultimately accepts the agreement, she won’t do so willingly.

“If I end up voting for this package, it won’t be silently. I will be dragged to that position,” she said.

Senate Republicans were largely positive in response to the agreement that was announced Monday night. However, mindful that the agreement hinges on Obama persuading enough Democrats to support the deal, Republican leaders urged their Members during a closed-door briefing to avoid excessive crowing about getting a full extension of the Bush tax cuts, a Republican said Tuesday.