Jonathan Chait tells you what you already know, but does it eloquently. The Republicans in congress are threatening to destroy the credit of the U.S. government and crash the global economy in order to prevent people with pre-existing conditions and low income workers from getting health care; and low-wage workers from having enough to eat.
In case you think it's a mystery why they would do this, let me clue you in. It is and always has been bedrock of the conservative psyche that my possessions and my enjoyments are worth much less to me if everybody else has them too. After all, privilege depends on the deprivation of others. What good is abundance if the undeserving -- be it the dark complexioned, the foreigner, the servant class -- get to share in it.
In the U.S. today, as has been classically true throughout history, the economically privilege have allied with the religious establishment to mutually preserve their prerogatives. Here again is the famous essay by Philipe E. Agre:
From the pharaohs of ancient Egypt to the self-regarding thugs of ancient Rome to the glorified warlords of medieval and absolutist Europe, in nearly every urbanized society throughout human history, there have been people who have tried to constitute themselves as an aristocracy. These people and their allies are the conservatives.
The tactics of conservatism vary widely by place and time. But the most central feature of conservatism is deference: a psychologically internalized attitude on the part of the common people that the aristocracy are better people than they are. Modern-day liberals often theorize that conservatives use "social issues" as a way to mask economic objectives, but this is almost backward: the true goal of conservatism is to establish an aristocracy, which is a social and psychological condition of inequality. Economic inequality and regressive taxation, while certainly welcomed by the aristocracy, are best understood as a means to their actual goal, which is simply to be aristocrats. More generally, it is crucial to conservatism that the people must literally love the order that dominates them. Of course this notion sounds bizarre to modern ears, but it is perfectly overt in the writings of leading conservative theorists such as Burke. Democracy, for them, is not about the mechanisms of voting and office-holding. In fact conservatives hold a wide variety of opinions about such secondary formal matters. For conservatives, rather, democracy is a psychological condition. People who believe that the aristocracy rightfully dominates society because of its intrinsic superiority are conservatives; democrats, by contrast, believe that they are of equal social worth. Conservatism is the antithesis of democracy. This has been true for thousands of years.