All put together, it’s a fascinating picture of the emergence of very strong party discipline of the sort that hasn’t traditionally existed in the United States and continues not to exist in the Democratic caucus. In lots of countries the way things work is that once a party caucus has decided on a position, all members vote for it even if in the intra-caucus dispute they didn’t want to adopt that position. But American parties don’t normally work this way. Camp, however, seems to be saying that the House GOP now does. Indeed, party decision-making is sufficiently centralized that discipline can be imposed even when the members are well-aware that the line people being made to toe is unpopular.
There's really no parallel to this on the Democratic side. The closest one can think of happened when the House managed to pass a cap-and-trade bill in 2009, which ending up stranding House members and going nowhere. Take that as a baseline, and add a few changes. First, the Ryan budget is way more unpopular than cap and trade. There are ways to spin cap and trade to make it popular. Thrush and Sherman quote Republican pollsters freely conceding that wasn't the case with Ryan's budget. Second, cap and trade had a chance in a heavily Democratic Senate, whereas House Republicans walked the plank for a bill that has no chance of becoming law this term. And finally, where cap and trade squeaked through, the House got all but four of its members to vote yes. They didn't even release vulnerable members to vote no. It's simply impossible to imagine democrats doing anything like this.
Yglesias wishes the press paid more attention to this asymmetry:
One of the unfortunate things about the political media’s commitment to “balanced” coverage is that not only do reporters generally feel impelled to always act as if the two parties are normatively symmetrical there also seems to be a reluctance to explore the systematic asymmetries between the parties in an even merely descriptive sense.
I agree. Of course, the media's commitment to normative balance is precisely the reason why it can't explore the asymmetry in party discipline. The media is deeply committed to the (usually wrongheaded) view that partisanship is bad. By this way of thinking, to acknowledge that one party's members are more partisan than the other party's would be an act of bias. Indeed, it would be an act of partisanship, and a contribution to all that ails Washington!