New START ratification appears to hinge largely on the position that McCain and his allies take. Despite what you may have heard about his tentative support, McCain’s remarks during the treaty debate have been largely discouraging for treaty supporters. If McCain diverts deliberations over the treaty into a debate over the internal affairs of Russia, and it seems that he wants to do just that, we already know the position McCain will take, and that will be the inflexibly anti-Russian position in which voting against the treaty will serve as a rebuke to the Kremlin. It would hardly be the first time that McCain has argued for jeopardizing U.S. interests for the sake of an irrational anti-Russian pose.

McCain has made it clear that he intends to introduce a missile defense amendment to the treaty this afternoon. If this is an amendment to the preamble, as I suspect it is, it is worse than worthless. This amendment will almost certainly be rejected, as any amendment will further delay ratification and could potentially wreck the entire agreement, and so we should assume that McCain will then claim that he cannot accept the treaty in its current form. Graham and Brown will probably follow his lead, and this will give Corker cover to jump into the anti-ratification camp. Assuming that Isakson and Murkowski are “yes” votes, that gives the treaty six Republican votes. If McCain opposes the treaty, Graham, Brown, and Corker will have to vote for it if it is going to pass. However, if McCain opposes the treaty by invoking missile defense, as he seems likely to do, Graham and Brown will follow suit.

Even if it did pass, it would be the narrowest margin for a successful treaty of this kind that there has ever been. Unfortunately, I still expect that the treaty will not be ratified this year, but I will be delighted to be wrong.

Update: Daniel Foster reports that McCain and Graham are inclining towards opposition, and Corker may be as well. Corker objects to the stand-alone “don’t ask, don’t tell” repeal being brought up this weekend. Obviously, voting down an important treaty to register a complaint about a completely separate matter would be petty, but the fate of the treaty may be partly decided because of opposition to an unrelated measure.

Second Update: It’s possible to read Corker’s remarks as a warning from someone sympathetic to the treaty rather than a threat to vote against it, but the danger to the treaty remains.

Third Update: I’m watching the debate on McCain’s amendment, which is indeed an attempt to strip out the preamble language referring to defensive weapons. As I said, it’s worse than worthless, and it confirms that McCain will not support the treaty. Foster has updated his post to include Graham’s objection to the preamble language:

Senator Graham, in remarks just now on the Senate floor, said New START’s preamble, which many believe contains an implicit limitation on U.S. missile defense, should be taken out of treaty, or else it “would be better not to do the treaty.” “You should not sign the treaty” without losing the preamble, Graham said.