Though a cloture vote on the New START treaty could be delayed until Wednesday, the measure now appears to be on a glide path to passage in the Senate by Wednesday night. 

Republican Senator Johnny Isakson of Georgia has announced his support as Senate Foreign Relations Committee Chairman John Kerry, D-Mass, has continued to negotiate amendments with Republicans. 

Kerry has also secured the support of Sen. Lamar Alexander, R-Tenn., picking up a critical vote in favor of the treaty and sources say Sen. Judd Gregg, R-NH, is very likely a 'yes' on START, as well.

Supporters feel confident that along with the likely support of Sen. Bob Corker, R-Tenn., they have the votes needed for ratification.

Meanwhile, START looks like it has lost the support of one Republican, Sen. Lindsey Graham of South Carolina, who is scheduled to appear at a news conference today on the treaty with lead skeptic, Sen. Jon Kyl, R-Ariz, who has said, emphatically, he is a 'no' vote if the roll is called before Christmas Eve.

Graham signaled his opposition to START on Sunday when he said he his is now waiting to hear from the Russians on missile defense, as the senator seeks assurances from all quarters that the development of this missile shield will not be delayed or weakened by ratification of this treaty.

Previously, Graham had sought, and received, assurances from President Obama, but Tuesday, he signaled his opposition again telling FOX that if Russia's position was for the United States to take this treaty or leave it, then "I've told our Russian friends I'll leave it."

Graham is among those GOP senators treaty supporters thought they would get, as they look to secure the support of at least nine members ahead of a ratification vote that requires a two-thirds majority of those present and voting.

Fox producer Wes Barrett contributed to this report.