By “success”, I mean reignition of the credit engine in high-income deficit countries. So private sector spending surges anew, fiscal deficits shrink and the economy appears to being going back to normal, at last. By “failure” I mean that the deleveraging continues, private spending fails to pick up with any real vigour and fiscal deficits remain far bigger, for far longer, than almost anybody now dares to imagine. This would be post-bubble Japan on a far wider scale.

Unhappily, the result of what I call success would probably be a still bigger financial crisis in future, while the results of what I call failure would be that the fiscal rope would run out, even though reaching the end might take longer than worrywarts fear. Yet the big point is that either outcome ultimately leads us to a sovereign debt crisis. This, in turn, would surely result in defaults, probably via inflation. In essence, stretched balance sheets threaten mass private sector bankruptcy and a depression, or sovereign bankruptcy and inflation, or some combination of the two.

I can envisage two ways by which the world might grow out of its debt overhangs without such a collapse: a surge in private and public investment in the deficit countries or a surge in demand from the emerging countries. Under the former, higher future income would make today’s borrowing sustainable. Under the latter, the savings generated by the deleveraging private sectors of deficit countries would flow naturally into increased investment in emerging countries.