Matthew Yglesias, who I think is sometimes contrarian for its own sake, nonetheless nails it in this essay.

The best point for me is here:

For veteran Washington hands—wheelers and dealers in the lobbying game or at the major interest groups—the new system is worse than dull. It’s emasculating. This is why political elites find polarization so distasteful. In a polarized world, elections and procedural rules largely determine policy outcomes; there’s little room for self-styled players to construct coalitions on the fly, and enhance their own power in the process. The growth in the lobbying industry might seem to belie the point, but consider Tom DeLay’s post-1994 “K Street Project”—which pressured lobbying firms who wanted access on the Hill to hire more Republicans—or the swing of the pendulum back after the Democratic takeover in 2006. Power in Congress is firmly in the hands of the party leadership; lobbyists become less powerful, not more, in a polarized system.

The fact is that outside of the beltway, no one really cares what David Broder thinks, or what gets said at Sally Quinn’s parties, and if you have a political system in which party affiliation actually means something, neither do the members of Congress or the Executive branch.

They answer to the voters under those circumstances.