As I've been saying, the procedural critique of the Senate that some of us have been making for years is starting, but only starting to make headway into the conventional wisdom. The Wall Street Journal's Gerald Seib (who writes a centrist column for the news section) concedes that the filibuster has risen to unprecedented levels, but still sees disappearing comity and centrism as the primary culprit of Senate dysfunction:

Perhaps most important, the band of conservative Democrats and liberal Republicans who stand in the ideological center of the Senate, providing a human bridge between left and right, has grown thin. As recently as the administration of the first President Bush, the Republican White House could often find support among a healthy contingent of Southern Democrats such as Sam Nunn of Georgia, and Howell Heflin of Alabama, while having to worry about whether liberal Northeastern Republicans such as John Chafee of Rhode Island and Jim Jeffords of Vermont would hew the party line.
The middle ground such senators represented is lonelier now, and a more polarized Senate the result.
"I don't think it's broken," says Howard Baker, another former Senate majority leader. "I think it's not working well. But it's also a part of the system." That broader political system, more than the filibuster, is the problem.

Let's suppose Seib is right, and the big problem is the disappearance of the middle. How exactly do you solve this? The United States did have many decades of ideologically heterogeneous parties, with the Democratic Party containing right-wing Southern white supremacists along with liberals, and the Republican Party containing progressives along with conservatives. But that situation, highly unusual among democracies, was the residue of a racial apartheid system that no longer exists.

The creation of more ideologically-coherent parties is a natural trend, and it's hard to see how or why it will stop. Northern moderates vote for Susan Collins and Olympia Snowe, but they're going to join a Republican filibuster to stop even a health care bill they voted for. Arkansans who think Barack Obama is a dangerous socialist probably aren't going to want to keep Blanche Lincoln in the Senate any more. To the extent that moderates do win Senate seats these days, it's largely by obscuring the political choices before their electorate.

Even if you think the disappearing center is the problem to the dysfunctional Senate, there's no solution to it. You can't change who the voters decide to elect. What you can change is the rules governing the body.