Tom Mann and Norm Ornstein lamented changes in Congress that turned it into what they called the "Broken Branch" in 2006. Obviously, things have only gotten worse since then. Jonathan Chait of the New Republic has a good recent diagnosis that I largely share. He points to increased partisanship, disputes over political legitimacy, and a change in norms. He also notes that more obstructive tactics are just waiting to be discovered.
I'd make the same points in a slightly different way. Partisanship has become more strident because the parties have become more ideological and the redistricting process has tended to strengthen reliable-party constituencies. Questions of legitimacy have been major issues of partisan dispute since the 1990s: starting with Bill Clinton, each president has been viewed as fundamentally illegitimate by a large segment of the opposition party. In Congress, the ideological unity of the parties has reinforced party discipline.
The change in norms is, to me, even more troubling. For whatever reasons -- the way political news is covered, the benefits of stridency for fundraising, the locker-room competitiveness of the players -- even minor political disputes are treated as must-win great battles. Every day is D-Day; every battle is another Stalingrad.
In the Senate, this has led to filibusters or other obstruction on more nominations and almost all legislation. What used to be a last-ditch tool either to publicize a concern or block some broadly popular measure is now a routine device. In the House, it has led both parties, when in the majority, to block proposals by the minority.
I remember when Sen.Jesse Helms [R-NC] discovered that treaty texts could be amended, something not tried since the Versailles Treaty debates in 1919. Suddenly, everybody wanted to amend treaties rather than attaching reservations. Since there are more unused or undiscovered tools for mischief in the Senate's rules, Chait is right to expect more obstruction in the future.
The only remedies are shame from the attentive media and public and rejection by the voters. It would also help to undertake some of the measures urged by Mann and Ornstein to try to restore civility and collegiality in the legislative branch.