Ezra Klein provides one:
When House Republicans talk about cutting spending and the Obama administration talks about freezing spending, neither group is talking about the vast expanse of the government’s commitments. They’re looking at a small corner of the budget, the 12.3 percent known as non-defense discretionary spending. The stuff that’s not Medicare, not Medicaid, not Social Security or the military. It’s the odds-and-ends, so to speak.
The situation is thoroughly depressing. Washington seems to have finally gotten itself in the mood to cut deficits. Unfortunately, the cuts that result are likely to be unhelpful, or possibly counterproductive, as leaders slash useful programmes to the bone because they're too scared to talk about reining in health care spending, or cutting wasteful defence programmes, or raising taxes.
It's hard to imagine something worse than a bruising political battle that threatens to shut down the government or throw it into default. But a bruising political battle that threatens to shut down the government or throw it into default without doing a thing about the long-run budget problem would probably do it.