Sometimes, it’s worth taking a step back and realizing just how much our politics have changed in the last few decades. Here’s a famous quote from David Mayhew, the eminent political scientist, in his 1974 classic Congress : The Electoral Connection:

The fact is that no theoretical treatment of the United States Congress that posits parties as analytic units will go very far.

Later in the book, Mayhew waves away the possibility of exactly the sort of intense partisan warfare that we see in Congress today:

It is easy to conjure up visions of the sort of zero-sum politics parties could import into a representative assembly. One possibility — in line with the analysis here — is that a majority party could deprive minority members of a share of particularized benefits, a share of committee influence, and a share of resources to advertise and make their positions known. Congressional majorities obviously do not shut out minorities in this fashion. It would make no sense to do so; the costs of cutting in minority members are very low, whereas the costs of losing majority control in a cutthroat partisan politics of this kind would be very high. A more conventional zero-sum vision is the one in which assembly parties organize in disciplined fashion for the purpose of enacting general party “programs”; the battle is over whose program shall prevail. It should be obvious that if they wanted to, American congressmen could immediately and permanently array themselves in disciplined legions for the purpose of programmatic combat. They do not. Every now and then a member does emit a Wilsonian call for program and cohesion, but these exhortations fail to arouse much member interest. The fact is that the enactment of party programs is electorally not very important to members (although some may find it important to take positions on programs)…

Party leaders are chosen not to be program salesmen or vote mobilizers, but to be brokers, favor-doers, agenda-setters, and protectors of established institutional routines. Party “pressure” to vote one way or another is minimal. Party “whipping” hardly deserves the name. Leaders in both houses have a habit of counseling members to “vote their constituencies”… In fact neither party demands anything like a truth test of its members.

The times, they are a-changing. For more on the realities of the new Congress, see the excellent Boston Globe series from last year.