Imagine a world with a small current account deficit in the US, a somewhat larger deficit in the eurozone and a not too excessive Asian surplus. In such a world, economic commentators would no longer bang on about global imbalances and would have to find a different subject.

In the long run, such a world would require significant reform of the international monetary system. In the short term, a fall in the dollar's exchange rate would help get us there. And I note with some satisfaction that it is happening.

A lower dollar is desirable because it would help America achieve the right kind of recovery. The US economy is severely constrained by household and financial sector deleveraging and possibly by a permanent fall in potential growth. In the absence of another housing bubble and consumer boom, an export-led recovery is the best growth strategy the US could employ.