The Obama administration is increasingly signalling that the US will not continue to be the world's consumer and importer of last resort. The clearest statements came last month from Larry Summers , White House economics director, in a speech at the Peterson Institute for International Economics and in an interview with the Financial Times. The US, he said, must become an export-oriented rather than a consumption-based economy and must rely on real engineering rather than financial wizardry. Tim Geithner, the US Treasury secretary, and other top officials have spoken similarly of rebalancing US growth.

The logic of this new US position is not just economic. It is also strategic. Mr Summers has previously remarked on the tension between superpower status and net foreign indebtedness. US influence can be compromised if it is dependent on foreign investors to bail out its financial sector (as in the early part of this crisis) or to finance its fiscal profligacy (as China and other surplus countries have been doing for a long time). The US undoubtedly also recognises that it might not be able to finance large external deficits in the future at an acceptable price so to some extent it is making a virtue of necessity.

This long-run vision for US growth entails greater exports and probably a smaller current account deficit than where it is now (about 3 per cent of gross domestic product). Although Mr Summers did not and could not say so, the vision will require an end to the remaining overvaluation of the dollar. Studies by William Cline and John Williamson at the Peterson Institute suggest that holding the US current account deficit to something close to these objectives will probably entail a further real depreciation of the dollar, mainly against the Chinese renminbi and other Asian currencies.