Boris Shor: “Before yesterday’s election, the 60th [most liberal] senator was Ben Nelson. This ranking made Nelson uniquely powerful. . . . After Brown’s election, however, the picture changes. [Paul] Kirk, the appointed temporary replacement for Edward Kennedy who is estimated to be the third most liberal Senator, leaves. Brown, who’s to the left of Snowe but to the right of Nelson, enters. He therefore becomes that pivotal 41st vote to sustain a filibuster and deadlock legislation (or the 60th vote to end a filibuster and pass it).”