http://voices.washingtonpost.com/ezra-klein/2010/09/the_senate_as_a_collective_act.htmlThe Senate as a collective action problem
Most people know that the Senate can't do much of anything these days unless it can muster the votes to break a filibuster.
What fewer people know is that the Senate also depends on unanimous consent for its non-controversial functions. And as the name implies, unanimous consent requires, well, unanimity. One senator can bring the whole thing down -- or at least make it take a while. As Ian Millhiser says, "it may only take 60 votes to get something accomplished in the Senate, but it takes 100 votes to do so quickly." And the Senate does not have nearly enough time to do everything slowly. If it can't function through unanimous-consent agreements most of the time, it can't function.
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On some level, the Senate has always been riven by a collective action problem. If the individual senators and the two parties use the rules in the way that are rational for them, the chamber can't function. But
there've been norms that held both sides, and most senators, in check. As those norms dissolve and the payoffs of obstruction become clearer to everyone, the collective restraint that allowed the Senate to function breaks down. And then the rules need to change. That, of course, is why the Rules Committee has been holding hearings on the filibuster. We're rapidly approaching the point at which the people who benefit most from the chamber's strange procedures are going to have to face the fact that they've made it necessary for the Senate to get rid of them altogether.