Top Democrats appeared confident Monday that the Senate will ratify a long-stalled nuclear arms treaty with Russia this week, but also acknowledged that Republicans could further hold up the accord.

The No. 2 and 3 Senate Democrats — Dick Durbin (Ill.) and Charles Schumer (N.Y.) — said that nine Republican votes are still in play, which would be enough to ratify the New START, or Strategic Arms Reduction Treaty.

ADVERTISEMENT

"The president is working really hard on this. He's burning up the phone lines," Schumer said on ABC's "Good Morning America" program. "We do need nine or 10 Republican votes on this, and I do think we will get them."

Durbin said there are eight or nine GOP senators "who will help us make this treaty the law of the land," but cautioned during an interview on MSNBC's "Morning Joe" that if Senate Republican leader Mitch McConnell (Ky.) "lobbies against us, we won't even have those nine."

Schumer and Durbin's attitude shows that Democrats are cautiously optimistic they can score another victory after they passed President Obama's tax-cut deal and a repeal of the military's "Don't ask, don't tell" policy last week. 

START is the priority issue for the Senate heading into this week, the last before the Christmas break. The White House and Senate Democratic leaders have lobbied heavily to pass the treaty this year, calling it a key element of U.S. national security.

Majority Leader Harry Reid (D-Nev.) has scheduled a rare closed-door session in the old Senate chamber on Monday to discuss classified intelligence related to the details of the arms treaty, in part to allay the concerns of skeptical Republicans.

The Senate is then expected to take a cloture vote to end debate on the treaty. That vote, which requires the approval of 60 senators, is expected to pass more easily than final ratification, for which the support of two-thirds of voting senators is needed. 

After weeks of debate, ratification is still uncertain. Last week, a key test vote on START passed with the support of 66 senators, one shy of the 67 needed to approve the treaty if all 100 senators vote. 

Republicans have long objected to New START, expressing concerns over U.S. nuclear modernization and the country's missile defense capabilities. Some have also protested that Democrats are trying to cram it through without adequate debate before the year is out.

McConnell reiterated during a floor speech Monday morning that he will oppose the treaty. 

"First and foremost, a decision of this magnitude should not be decided under the pressure of a deadline," McConnell said. "The American people don’t want us to squeeze our most important work into the final days of a session. They want us to take the time we need to make informed, responsible decisions."