Adding to yesterday's post, it isn't that I think we should do nothing. We should spend less money on stupid wars. We should bring down the cost of our health care system, because we spend stupid amounts of money for a mediocre product, and a lot of that (most!) is government spending. But we shouldn't maintain the fantasy that any of these things will lower the deficit. If, for example, we reduce the rate of growth in health care costs, this means that future lawmakers will spend less money on health care than projected. It does not mean that the deficit will be lowered. It will only lower the deficit if lawmakers don't cut taxes on rich people or spend more money on future stupid wars.
My point is that, yes, we should make sensible policy decision, but sensible policy decisions have nothing to do with the deficit 20 years from now. We can't control that.