Sen. John McCain appeared unenthusiastic Wednesday about ratifying a long-stalled nuclear arms reduction treaty with Russia this year.

The Arizona Republican, who is the ranking member of the Armed Services Committee, said it would be a "good idea" to wait until January to debate and pass the Strategic Arms Reduction Treaty (START).


"I hope we can [ratify the treaty]," McCain said during an appearance on former GOP Sen. Fred Thompson's nationally syndicated radio show. "But right now I still have serious concerns about the missile defense part of it."

McCain's comments are another indication the treaty could be losing momentum in the Senate, where it needs 67 votes to be ratified.

Just last month, the 2008 GOP presidential nominee expressed hope the Senate could ratify the accord before the Senate ends its lame-duck session.

"I would hope so," he said when asked on ABC's "Good Morning America" if negotiations had advanced to the extent that a vote could be held by the end of the year.

Now, Sen. Jim DeMint (R-S.C.) plans to force a full reading of START and the omnibus spending bill, which could take days. But Senate Majority Leader Harry Reid (D-Nev.) has pledged to keep the upper chamber in session through the weekend — and possibly into next week — in order to complete work on both measures. 

The White House condemned DeMint's move as a "new low."

McCain has always acknowledged reservations about the treaty. On Thursday he acknowledged the worries of chief GOP negotiator Sen. Jon Kyl (Ariz.), who has expressed concern START could weaken U.S. missile defense and nuclear modernization. 

He backed Kyl's plan to bring up the pact the week of Jan. 24 and debate it for a week before holding a ratification vote.

The senator last week said that the treaty would only be a "modest accomplishment" and has criticized the Obama administration's effort to "restart" relations with Russia, pointing out that the countries lack common interests and shared values. 

Other signs emerged Thursday that GOP support to hold a December vote on START could be breaking.

Retiring Sen. Judd Gregg (R-N.H.), who said he is "leaning heavily toward" supporting the treaty, refused to condemn DeMint's maneuver.

"Well, that's the beauty of the Senate," Gregg said on ABC's "Top Line" webcast.