As it becomes increasingly evident that the recovery will remain subdued in Europe and the US, there is a growing chorus for indefinitely sustaining aggressive post-crisis fiscal stimulus. Governments that instead propose gradually reducing deficits and ultimately stabilising debt to income levels – such as both Germany and the UK – are accused of pig-headed fiscal conservatism. Had they only a better grasp of Keynesian truisms, we are told, these countries' leaders would realise that their penury risks throwing already weak economies into double-dip recessions, or even a sustained depression.

There is no question that huge uncertainty hangs over the global economy, but is the case against commonsense fiscal conservatism so compelling? I don't see it. Yes, output growth is likely to remain tepid compared with a normal post-recession recovery. As Carmen Reinhart and I have repeatedly emphasised in our research, anaemic growth with sustained high unemployment is par for the course in post-financial-crisis recoveries. Yes, Europe's sovereign debt and banking problems are unlikely to disappear soon. But sovereign debt problems are a typical aftershock of any wave of international financial crises. Worrisome as the current conjuncture may seem, the normality of the crisis trajectory to date hardly suggests the need for a panicked fiscal response.

Indeed, it is folly to ignore the long-term risks of already record peace-time debt accumulation. Even where Greek-style debt crises are unlikely, the burden of debt will ultimately weigh on growth due to inevitable fiscal adjustment. The fact that the markets seem nowhere near forcing adjustment on most advanced economies can hardly be construed as proof that rising debts are riskless. Indeed, the evidence generally suggests that the response of interest rates to debt is highly non-linear. Thus, an apparently benign market environment can darken quite suddenly as a country approaches its debt ceiling. Even the US is likely to face a relatively sudden fiscal adjustment at some point if it does not put its fiscal house in order.