One of the biggest foreign policy challenges facing the next US president will be how to modernise the main forums of global decision-making. Crises in Iraq, Afghanistan and Iran will consume much of his time, but Barack Obama or John McCain must lead the way in making the United Nations and other institutions more relevant to our age. Otherwise, the influence of the US will continue to wane.

The place to start is to abolish the annual summits of the Group of Eight leading industrial nations in favour of the Group of 20, which draws members from all continents, represents two-thirds of the world’s population and accounts for 90 per cent of all economic activity. In contrast, the G8, which was formed in 1976 and whose leaders will meet next week in Tokyo, excludes such rising powers as China, India and Brazil and governs just more than one-tenth of the world’s inhabitants.