Those (many) who are rubbishing the eminently rubbishable S&P tonight are generally not grappling with something we've been talking about for years around these parts: The current fiscal trajectory of the United States is not just deteriorating rapidly, it's definitionally unsustainable. That's not crazy libertarians talking, that's Barack Obama and Ben Bernanke.
As Peter Suderman rightly pointed out as the ink on the debt-ceiling deal was still drying,
[I]t won't be nearly enough. In the long term, the biggest driver of the federal debt growth is health spending, and while the deal that's now hurtling toward a vote might result in some tweaks to the payments the government makes to health care providers, it essentially does nothing to combat the unsustainable long-term growth of health spending. [...]
The best reason to have a big showdown over raising the debt limit was to start the process of figuring out how to deal with a federal fiscal trajectory that is simply not sustainable. Instead, we ended up with a politically motivated showdown that resulted in gimmick-filled plans full of likely-bogus spending reductions and that, if anything, ultimately made our credit outlook slightly worse by illustrating, in painful and prolonged detail, how difficult it will be for our political system to truly come to terms with the nation's debt problem when it eventually has to.
Blame S&P all you want, but this won't be the last downgrade; the math really is that bad. As Sen. Rand Paul (R-Ky.) is fond of saying, Democrats are going to have to give on entitlements, and Republicans are going to have to give on military spending, as a starting point. There really isn't any other way.
I eagerly look forward to this being blamed on libertarians, but even more than that I truly look forward to the day when the political class in this doddering country recognizes that you can't just wave away a spending spiral by pretending that it doesn't exist.