Should Mario Draghi ever want to start raining down helicopter money, the ECB president is likely to struggle to get off the ground.

The deeper the slump, economists used to say, the stronger the recovery.

Insanity, we are told, is doing the same thing time and again and expecting a different solution. By that definition — and this will come as no surprise to anyone who has watched the slow-motion train wreck that is the eurozone — the ECB is insane.