Dear Mario,

Congratulations and commiserations: next week, you will take up one of the most important central banking jobs in the world; but you will also bear a frightful responsibility. The European Central Bank alone has the power to quell the eurozone crisis. You must choose between two paths: the orthodox one leads towards failure; the unorthodox one should lead towards success.

The eurozone confronts a set of complex longer-term challenges. But the members will not get the chance to make needed adjustments and implement required reforms if it does not survive. The immediate requirements include putting Greece on a sustainable path; avoiding a meltdown in public debt markets of several large countries; and preventing a collapse of banks. Of these, it is the last two that matter.