The New START Treaty was ratified by the Senate by a vote of 71 to 26. Thirteen Republicans decided that national security was more important than party politics. Vice President Joe Biden presided over the vote.
Fred Kaplan has probably the best analysis of the politics of the ratification. He sees Jon Kyl and Mitch McConnell as the big losers. It will be interesting to see what effect this might have on the next Congress.
Particular credit goes to the Republicans voting to ratify the treaty:
Full vote here.