This time, the fight that matters is within the Republican party, and that fight is over whether compromise itself is legitimate.** Outsiders to this struggle -- the president and his administration, Democratic legislators as a group, voters or "opinion leaders" outside the generally safe districts that elected the new House majority -- have essentially no leverage in this fight. I can't recall any situation like this in my own experience, and the only even-approximate historic parallel (with obvious differences) is the inability of Northern/free-state opinion to affect the debate within the slave-state South from the 1840s onward.
You have a bunch of backwards-ass 'necks who think most of America's problems can be attributed to women, blacks, "illegal immigrants" by whom they mean anyone speaking Spanish in a department store, liberalism in general and the (black) president in particular. They hate science and they despise progress in all forms, especially if happens to have the side benefit of not actively polluting the environment and/or making someone's life a little easier.
Their world is slipping away from them, as the rest of the civilized universe moves forward with marriage for all, public transporation, protection of workers and minority rights, and universal health care. Their world, the palatial estate in which they ruled absolutely, is collapsing around them. They've been trying for the last 30 years to wall themselves off in their power centers and now even if they can't see the pitchforks and torches, they sure as shit can smell the smoke.
Their supporters are desperate, angry, and armed. They've been told for three decades at least that the only way to fix everything wrong in their lives is to elect some Republican to step on a liberal's neck. They've been fed a constant diet of rage through their radios and TVs, and they've seen almost nothing to counter it because things do suck right now, and none of it is the fault of an ordinary guy who gets up and goes to work. So naturally in 2010 and again in 2012 they elected a bunch of Republicans, really dumb ones, whose only unifying platform was fuck you.
Now somebody has to get fucked, because otherwise what was the point? What was the point of all that tea partying, of every ten dollars somebody couldn't afford to spend that went to a candidate, what was the point of it? What was the point of all that end-of-the-world rhetoric if the world doesn't actually end? You've stocked a bunker for the apocalypse, so come on, don't try to tell me you won't be kind of disappointed if instead of four vengeful horsemen you get a drunk clown on a pony.
The people they elected set the world careening for destruction a thousand miles an hour so they wouldn't have to face a lick of change, and now the momentum's overtaken them. Lots of men and women ended up dead for it the last time we acted like this, the last time a bunch of people decided to cut the country in two out of spite. I'd like to say we learned our lesson and this time let's LET THEM. Just give them a state or two, where they can sing their songs and bang their drums and hate on gays and not bother any of us anymore, and the rest of us can get on with the 21st century.
The thing is, though, nobody deserves what's about to happen. Not Republican voters, not Democratic voters, not ordinary people watching TV and seeing a world that makes no sense to them anymore. I'm not angry enough to wish punishment on people who did nothing to deserve this, who elected representatives to fix problems, even if the solutions those representatives offered had no chance of succeeding. The only people who "deserve" a government shutdown, the only people who "deserve" the civil war we're making, are the people who will never feel the pain of it, whose townhouses and luxury cars and vacation homes will remain untouched by the misery they'll inflict.
The bankers and Congressmen and lobbyists and money guys, the princes of darkness who make all our decisions now, the craven apologists in the national press for the same, those people aren't going to reap what they've sown. They aren't going to lose jobs, houses, families, friends. They aren't going to get sick and die in bankruptcy. They aren't going to be foreclosed on and tossed out in the street.
They'll glide on through life without a moment's trouble no matter if the world crashes and burns. They won't suffer. They have people to do that for them.