Obligatory caveat: yes, we have a long-run budget problem, and we should be taking steps to address that problem, mainly by reining in health care costs. But it’s simply crazy to be laying off schoolteachers and canceling infrastructure projects at a time when investors are offering zero- or negative-interest financing.

You don’t even have to make a Keynesian argument about jobs to see that. All you have to do is note that when money is cheap, that’s a good time to invest. And both education and infrastructure are investments in America’s future; we’ll eventually pay a large and completely gratuitous price for the way they’re being savaged.

That said, you should be a Keynesian, too. The experience of the past few years — above all, the spectacular failure of austerity policies in Europe — has been a dramatic demonstration of Keynes’s basic point: slashing spending in a depressed economy depresses that economy further.