Whoever moves into the Oval Office in January 2009 will have to deal with a significantly different global economy from the one George W. Bush inherited just eight years earlier – and will need to forge a very different set of policies to address it. The most dramatic changes are that the emerging economies – most notably Brazil, Russia, India and China (the Brics) and the big oil exporters – now play a far greater role in the world economy than they did then, and that the US is now a great deal more dependent on their financial decisions, economic policies, capital and markets.

Since 2001, the US share of world gross domestic product has fallen from 34 per cent to 28 per cent, while that of the Brics has risen from 8 per cent to 16 per cent. China’s reserves have rocketed from $200bn to $1,800bn, Brazil’s from $35bn to $200bn, Russia’s from $35bn to $500bn and India’s from $50bn to $300bn. World oil consumers have tran­sferred more than $3,000bn to exporters. Because of America’s very low savings rate and heavy reliance on credit, US consumers, companies, financial institutions and the federal government must borrow heavily from these countries. The dollar now has a world-class competitor, the euro, which accounts for nearly 30 per cent of all international currency reserves, a proportion rising fast. And US trade, especially with emerging economies, is climbing as a portion of GDP, with fast-growing exports now giving the economy a desperately needed boost.