We are now just hours from a possible government shutdown and just days from a possible debt crisis. James Fallows has a nice piece up explaining that these situations are not simply the result of "gridlock," despite many journalists' (understandable?) efforts to frame the story as a both-sides-do-it situation. Yes, gridlock is a problem when one party controls a chamber of Congress and another controls the White House, preventing them from working on collective goals, but inaction really isn't the problem here.
Similarly, some have sought to portray the current double-crisis as a consequence of polarization. Well, polarization contributed to this, but that's hardly everything that's going on. Polarization simply means that the major parties have moved apart from each other ideologically. (It can also mean that they've grown more internally cohesive. Both have happened.) But polarization is more a necessary condition than a cause. The proximate cause of this crisis is norm violation by one party.
That is to say, one party has developed tools -- and an apparent willingness to use them -- that the other party has not. House Republicans, notably, have developed a list of policy demands (including, prominently, the delay or repeal of existing law), and have refused to pass a continuing budget resolution that doesn't meet those demands. This is, needless to say, not the typical means by which policy goals are met in the American political system. But unless their demands are met, they say, there will be no bill to fund the federal government tomorrow. Republicans have demonstrated their willingness to use this rather blunt tool in the past, as manifested in a multi-week shutdown during the winter of 1995-96. (Please see my recent posts at Pacific Standard -- here and here -- for some discussion of the consequences of that shutdown.)
A government shutdown would be damaging -- for government employees, for those who depend on its services, and ultimately for the economy -- but would likely be just a minor cold compared to what the refusal to raise the debt ceiling would be. Yet House Republicans are apparently prepared to do just that if their policy demands are not met. We've not yet crossed that rubicon, although we came close a few years ago.
Democrats have faced similar political environments yet notably not utilized such tools in the past. Democrats took control of both chambers of Congress in 2006, for example, after a campaign that largely emphasized opposition to the Iraq War. In theory, Speaker Pelosi could have insisted on a 100-day pullout for all US soldiers in Iraq as a condition for raising the debt limit, which was raised in September of 2007. She did not. No such conditions were attached to the continuing budget resolution passed in January of 2007, either. Now, even if she had tried something like this, her coalition might have fractured pretty quickly. Regardless, there were devastating tools at the Democrats' avail, but they nonetheless chose to press their policy goals through fairly typical legislative procedures.
Republicans right now are pushing highly unorthodox and potentially very dangerous methods to achieve their goals. It's probably fair to say that as long as potential veto points like debt limit votes or the filibuster are lying around, a determined enough minority will eventually use them. But for whatever reason, it's the Republicans that are using them right now.
An additional note: Many political scientists -- myself included -- are somewhat uncomfortable writing about these sorts of partisan asymmetries. It's pretty easy to be labeled a hack for pointing them out. Nonetheless, they're occurring, and we do our discipline no favors by pretending they're not.