So, this is the way budget negotiations usually work: The Democrats want higher taxes so that they can spend more money on the poors, the olds, the kids, the coloreds, and other societal parasites, while Republicans want lower taxes on the wealthy and want to spend less money on everybody except the military (and military contractors) and of course prisons (because we have to do something about all those parasitic poors, olds, kids, and coloreds, and all the sex and abortions they're having)!
Or something. Stereotype it anyway you want. But the point is, budget negotiations are usually about budget priorities: How much to spend, where to spend it, and how to raise the revenue. And in a typical budget negotiation, each side agrees to stuff it doesn't want in exchange for stuff it does, depending on the relatively strength of the two parties. For example, House Republicans might eventually drop their demand to slash $40 billion from food stamps in exchange for $40 billion of cuts elsewhere. (Maybe. Or maybe they just like to take food out of the mouths of hungry children. I dunno.)
But what we never see as a sticking point in these negotiations are points of agreement—you know, stuff that both sides want. For example, even in the midst of our ongoing government shutdown, essential services are left untouched. Our armed forces continue to be paid and resupplied. Our federal prisons continue to operate. Nobody's fighting to get rid of either, and so both are off the negotiating table.
Which brings us to the debt ceiling. In the past, the debt ceiling has never been held hostage as a negotiating tactic because presumably neither party wants to destroy the full faith and credit of the United States Government, neither party wants our nation to sacrifice the enormous economic advantages that come from the dollar serving as the world's unchallenged reserve currency, and neither side wants to risk the incalculable cost of plunging the nation and the world into a steep economic collapse. Except now, apparently, the Republicans do, for how else to understand the Republicans' offer to trade a hike in the debt ceiling for the death of Obamacare?
Either Republicans really don't understand the consequences of default—in which case they're crazy—or they are holding a gun to their own heads—in which case they are crazy. Either way, I'm not sure how you negotiate with crazy.