OK, maybe a more polite way to say it is this: bad ideas are acting as serious constraints on policy.

We’re in a liquidity trap, with interest rates up against the zero bound. This means that conventional monetary policy isn’t sufficient. What should we do?

The first-best answer — that is, the answer that economic models, like my old Japan’s trap analysis, suggest would be optimal — would be to credibly commit to higher inflation, so as to reduce real interest rates.

But the key thing to recognize about this answer is that it’s all about expectations — the central bank only has traction over expected inflation to the extent that it can convince people that it will deliver that inflation after the liquidity trap is over. So to make this policy work you have to (i) convince current policymakers that it’s the right answer (ii) Make that argument persuasive enough that it will guide the actions of future policymakers (iii) Convince investors, consumers, and firms that you have in fact achieved (i) and (ii).

In reality, we haven’t even gotten anywhere near (i): the conventional wisdom is still that any rise in expected inflation above 2 percent is a bad thing, when it’s actually good.

So some readers have asked why I’m not making the same arguments for America now that I was making for Japan a decade ago. The answer is that I don’t think I’ll get anywhere, at least not until or unless the slump goes on for a long time.

OK, so what’s next? The second-best answer would be a really big fiscal expansion, sufficient to mostly close the output gap. The economic case for doing that is really clear. But Washington is caught up in deficit phobia, and there doesn’t seem to be any chance of getting a big enough push.

That’s why, at this point, I’m turning to what I understand perfectly well to be a third-best solution: subsidizing jobs and promoting work-sharing.

Call it constrained optimization, where the constraint comes from the power of bad ideas.