Krugman notes the real reason Conservatives love austerity:
So why have so many politicians insisted on pursuing austerity in slump? And why won’t they change course even as experience confirms the lessons of theory and history?
Well, that’s where it gets interesting. For when you push “austerians” on the badness of their metaphor, they almost always retreat to assertions along the lines of: “But it’s essential that we shrink the size of the state.”
Now, these assertions often go along with claims that the economic crisis itself demonstrates the need to shrink government. But that’s manifestly not true. Look at the countries in Europe that have weathered the storm best, and near the top of the list you’ll find big-government nations like Sweden and Austria.
And if you look, on the other hand, at the nations conservatives admired before the crisis, you’ll find George Osborne, Britain’s chancellor of the Exchequer and the architect of the country’s current economic policy, describing Ireland as “a shining example of the art of the possible.” Meanwhile, the Cato Institute was praising Iceland’s low taxes and hoping that other industrial nations “will learn from Iceland’s success.”
So the austerity drive in Britain isn’t really about debt and deficits at all; it’s about using deficit panic as an excuse to dismantle social programs. And this is, of course, exactly the same thing that has been happening in America.
My emphasis. As I've said before, arguments about economics tend not to be about science, but about morality. Krugman and Keynes point has been endlessly demonstrated in the data, and the objections fail on logic as well.