For the past 70 years the US has sought to lead and expand an open, democratic international order. During the cold war it promoted multilateralism in the west and waged a long struggle against the Soviet Union. Since 1991 it encouraged expansion of globalisation and democracy, although in very different ways under President Bill Clinton and the two presidents Bush.

This era of expansion is drawing to a close. China shows no signs of democratising as it grows wealthier. The financial crisis has undermined the lure of open markets. And difficult wars in Iraq and Afghanistan have made Americans sceptical of nation building and promoting democracy.

The pre-eminent question now for US policymakers is how to preserve the American-led international order amid a series of dramatic geopolitical changes. Can emerging powers, especially China, be accommodated without rendering useless the core tenets of the international order? Should the US be preparing to do more or less abroad as its relative power declines?