Actually, if you were paying the slightest bit of attention to how the Senate works now, and the politics within the Republican seats, you'd know your point doesn't stand at all.
Not that you'll believe it anyway, but for the sake of everyone else who's curious: The split is really 57-41, with two Independent senators. One is a Democrat in all but name, but the other is Joe Lieberman, who basically turned into a Republican in all but name out of spite for being ostracized by what used to be his party. Since a filibuster only needs 40 votes, that means 57 Democrats, the 1 Socialist, and at least three Republicans. There's exactly two Republican senators who could reasonably be called "most liberal" (Snowe and Collins). They, like every other Republican in the Senate, know that if they make one move against Boehner's demand to filibuster everything, they'll lose all their Committee seats and Republican Conference campaign support, let alone earn the ire of the RNC for daring not to anchor themselves to the wingnut tidal wave.
Not that I don't think Harry Reid isn't the biggest limp-wristed milksop ever to worm his way into leadership of anything. I'm actually hoping he loses in November, just to shake things up.