Republican senators that vote for the new START nuclear arms treaty with Russia will have to do so against the wishes of GOP leadership.
Senate Majority Leader Mitch McConnell (R-KY) and Minority Whip Jon Kyl (R-AZ) both said Sunday that they will oppose passage.
"I've decided I can not support the treaty," McConnell told CNN's Candy Crowley. "I think the verification provisions are inadequate. And I do worry about the missile defense implications of it."
Supporters argued that the amendment would have killed the treaty because it would have required the the US to conduct further negotiations with Russia.
The vote came after President Barack Obama sent a letter to McConnell and Senate Majority Leader Harry Reid (D-NV) assuring them that the treaty would not hamper plans to development missile defense.
"Regardless of Russia’s actions in this regard, as long as I am president, and as long as the Congress provides the necessary funding, the United States will continue to develop and deploy effective missile defenses to protect the United States, our deployed forces, and our allies and partners," Obama wrote.
The president's letter did nothing to convince Kyl. "Look, tell it to the Russians. Send a letter to the Russians. In fact, change the preamble to the treaty, which would eliminate any doubt about this issue...That's why I say talk to the Russians. Don't send a letter to Mitch McConnell," he told Fox News' Chris Wallace.
But appearing on ABC Sunday, Sen. John Kerry (D-MA) disagreed said that the language in the treaty's preamble had no bearing on missile defense.
"There is no legal binding statement whatsoever," Kerry said. The language in the preamble "is a sort of statement that for political purposes was necessary to achieve what we achieved."