Go back two or three years and the issue that most occupied the best foreign policy brains was how America would (or should) deploy its unrivalled power in the wake of the terrorist attacks of September 11 2001. More recently, brows have furrowed over the strategic implications of President George W. Bush's determination to overturn the authoritarian status quo in the Middle East. Like much else, though, foreign policy is a slave to fashion. So the issue of the moment is no longer how the global system adjusts to the American imperium but rather how the US accommodates the world's rising powers, above all China.

The prosaic reality is that all three of these things will remake the geostrategic landscape in the coming decades. The huge uncertainties inherent in each of them - and in the interactions between them - do much to explain why that terrain is still wrapped in a dense fog. Logic says that a world free of cold war nuclear confrontation should be a safer place. But we have learnt that dangerous certainties can seem more reassuring than unpredictable upheavals.