The eurozone is in a form of limbo: it is neither so deeply integrated that break-up is inconceivable, nor so lightly integrated that break-up is tolerable. Indeed, the most powerful guarantee of its survival is the costs of breaking it up. Maybe that will prove sufficient. Yet if the eurozone is to be more than a grim marriage sustained by the frightening costs of dividing up assets and liabilities, it has to be built on something vastly more positive than that. Given the economic divergences and political frictions revealed so starkly by this crisis, is that now possible? That is the most difficult question of all.
