After passage of the tax-cut deal, as well as the repeal of "Don't Ask, Don't Tell," ratification of the New START arms-reduction treaty with Russia represents the final legislative drama during this lame-duck session of Congress.
Senate Majority Leader Harry Reid has scheduled a vote to end debate on treaty for Tuesday. That needs 60 votes to pass, which appears to be a given.
The uncertainty, however, is over ratification, which will need 67 votes -- so at least nine GOP votes -- and that action will come sometime after the vote to cut off debate.
One Republican who won't be voting for ratification is Senate Minority Leader Mitch McConnell, who said yesterday: "I think the verification provisions are inadequate and I do worry about the missile defense implications of it... I think if they'd taken more time with this -- rushing it right before Christmas, it strikes me as trying to jam us. I think if they'd taken more time --I know the members of the Foreign Relations Committee spent a lot of time on this but the rest of us haven't."
But the White House says it was never counting on McConnell's vote. "We respect Sen. McConnell's view, but weren't surprised by it, and we certainly weren’t counting on his vote," said White House spokesman Tommy Vietor.
Democrats remain optimistic they have the votes needed for ratification, as Vice President Joe Biden said on "Meet the Press" yesterday.
But make no mistake, the effort won't be easy.