The Senate's top Democrat said Monday he's hoping not to have to work through the Christmas holiday, but he wouldn't rule it out.

Though the Senate managed to clear some key items off its agenda over the weekend, unfinished business means the upper chamber could be working Christmas Eve, as senators were forced to do last year to wrap up work on healthcare reform.

"Last year we were here at this time until Christmas Eve," Senate Majority Leader Harry ReidHarry ReidConservative Senate candidate calls on GOP to end filibuster Ex-Reid aide: McConnell's 'original sin' was casting ObamaCare as 'partisan, socialist takeover' GOP faces growing demographic nightmare in West MORE (D-Nev.) said Monday morning on the Senate floor. "I hope we don't have to do that again this year."

Unfinished business facing lawmakers includes action on a continuing resolution to fund government for the next few months, confirmation for some of President Obama's nominees and ratification of the New START Treaty with Russia.

The Senate's progress on that treaty could be key to determining the length of the workweek. The chamber approved a repeal of "Don't ask, don't tell" and voted down the DREAM Act over the weekend, clearing those items off the schedule.

The intense schedule comes after Reid traded barbs last week with Republicans over whether it's appropriate to work during the Christmas holiday. Some GOP senators said that doing so was "sacrilegious," a claim Reid called "sanctimonious."

The Nevada Democrat has threatened work through Christmas and New Year's Eve, if necessary, though those threats have prompted lawmakers to strike agreements to clear business before this weekend's holiday.

Reid filed cloture on the treaty Sunday, setting up a test vote for Tuesday. The treaty needs 67 votes for ratification, and the Senate will go into a rare, closed-door session Monday afternoon to debate the agreement between the U.S. and Russia.

One top Democrat, Sen. Charles SchumerCharles SchumerTrump: Why aren't 'beleaguered AG,' investigators looking at Hillary Clinton? Trump: Washington ‘actually much worse than anyone ever thought’ Schumer: Dems didn't 'tell people what we stood for' in 2016 MORE (D-N.Y.), said this morning that nine or 10 Republicans would be needed to secure ratification on the agreement.

Reid pleaded with Senate Minority Leader Mitch McConnellMitch McConnellMcCain returning to Senate in time for health vote Senate Dems launch talkathon ahead of ObamaCare repeal vote Overnight Healthcare: Trump pressures GOP ahead of vote | McConnell urges Senate to start debate | Cornyn floats conference on House, Senate bills | Thune sees progress on Medicaid MORE (R-Ky.) to allow expedited work on the continuing resolution amid the treaty debate in order to allow lawmakers to finish up their work as soon as possible.