The prospects of the Senate considering the new Strategic Arms Reduction Treaty during the lame-duck session are growing increasingly dim, Majority Whip Dick Durbin (D-Ill.) said Monday.

President Barack Obama signed the treaty with Russia earlier this year and has made Senate ratification of the document his top foreign policy priority before the sun sets on the 111th Congress. But Durbin conceded that Republican resistance could push the ratification debate to next year, despite Majority Leader Harry Reid (Nev.) insisting that it remains on the Democrats’ list of items to address before Christmas.

Durbin said he was discouraged by comments made over the weekend by Minority Whip Jon Kyl (Ariz.), the lead Republican negotiator on START. Treaty ratification requires 67 votes — seven more than is required to overcome a filibuster. 

“I’ve got some mixed signals here,” Durbin said Monday afternoon during a brief interview. “There are some on the Democratic side that thought we were in good shape to call it before we left, and to act on it. And, then over the weekend, Sen. Kyl said it would not be called during the lame-duck session. So, I can’t tell you exactly where we are today.”

Kyl, appearing on CBS’ “Face the Nation” Sunday with Durbin, indicated that there was not enough time to adequately debate START given Democrats’ legislative priorities for the lame duck reiterated by Reid Monday afternoon. Reid made clear Democrats want to dispose of a “long to-do list” of legislation, in addition to extending the 2001 and 2003 tax cuts that are set to expire at the end of the year.

Republicans have previously said that they might be amenable to debating START in the lame duck if the Democrats focus solely on taxes and approving funds to keep the government operating into 2011. But even if Reid were to pare back the list of proposed legislation Democrats want addressed this month, the Republicans appear unlikely to provide the votes needed for START to be ratified.

The notion of pushing START to 2011 — when a Senate that includes a Republican minority of 47 Members can debate it — has gained traction among GOP activists and in the conservative blogosphere. Additionally, more than half of the 42 Republican Senators have said they will oppose the treaty if it is brought up for debate in the lame duck.

Republican Sens. Jim DeMint (S.C.) and John Ensign (Nev.) penned a letter to Minority Leader Mitch McConnell (R-Ky.) last Thursday asking for his support to ensure that the START debate occurs next year. The letter was signed by 22 GOP Senators. Sen.-elect Roy Blunt (R-Mo.) last month wrote a separate letter to Reid, signed by nine of his incoming freshman GOP colleagues, asking that START be delayed until 2011.

One senior Republican Senate aide confirmed that these factors are weighing on Kyl as he determines how to proceed on START. “The letter is significant,” this source said Monday. “That’s half of our Conference who are publicly indicating they wouldn’t agree to START ratification this year.”

It is unclear if Kyl is even prepared to support the treaty on its merits. 

He has led the GOP opposition to START for several months in order to negotiate acceptable changes with the White House and secure guarantees on related policy issues such as funding to modernize existing U.S. nuclear stockpiles. The senior Republican Senate aide said Kyl’s timeline for revealing his final position on START remains in flux. 

Durbin said, essentially, that the treaty’s fate is in the Minority Whip’s hands.

“There’s no question that Sen. Kyl’s been in the driver’s seat in terms of the scheduling,” the Illinois Democrat said. “I hope that we’ve satisfied his concerns and we’ll give him ample opportunity for amendments if he wishes.”