I’ve actually been avoiding thinking about the latest Obama cave-in, on ozone regulation; these repeated retreats are getting painful to watch. For what it’s worth, I think it’s bad politics. The Obama political people seem to think that their route to victory is to avoid doing anything that the GOP might attack — but the GOP will call Obama a socialist job-killer no matter what they do. Meanwhile, they just keep reinforcing the perception of mush from the wimp, of a president who doesn’t stand for anything.

Whatever. Let’s talk about the economics. Because the ozone decision is definitely a mistake on that front.

As some of us keep trying to point out, the United States is in a liquidity trap: private spending is inadequate to achieve full employment, and with short-term interest rates close to zero, conventional monetary policy is exhausted.

This puts us in a world of topsy-turvy, in which many of the usual rules of economics cease to hold. Thrift leads to lower investment; wage cuts reduce employment; even higher productivity can be a bad thing. And the broken windows fallacy ceases to be a fallacy: something that forces firms to replace capital, even if that something seemingly makes them poorer, can stimulate spending and raise employment. Indeed, in the absence of effective policy, that’s how recovery eventually happens: as Keynes put it, a slump goes on until “the shortage of capital through use, decay and obsolescence” gets firms spending again to replace their plant and equipment.

And now you can see why tighter ozone regulation would actually have created jobs: it would have forced firms to spend on upgrading or replacing equipment, helping to boost demand. Yes, it would have cost money — but that’s the point! And with corporations sitting on lots of idle cash, the money spent would not, to any significant extent, come at the expense of other investment.

More broadly, if you’re going to do environmental investments — things that are worth doing even in flush times — it’s hard to think of a better time to do them than when the resources needed to make those investments would otherwise have been idle.

So, a lousy decision all around. Are you surprised?