The global standing of the UK is likely to decline in coming years as developments beyond Britain's shores wrest more and more influence on the island nation, writes Philip Stephens.
Gordon Brown declares that a strong voice on the international stage is central to his government's vision of Britain's future. In the same Churchillian tones, David Cameron proclaims that his Conservatives would restore the nation's prestige in the councils of world affairs. A distinguished military scholar takes a different view: the curtain is falling, he says, on a 400-year-old global adventure.
A general election campaign is not the moment for politicians to admit that the geopolitical tides are running against them. But whatever the outcome of the May 6 poll, Britain stands on the threshold of a wrenching reassessment of its place in the international order.
Beyond ritual tributes to the valour of troops fighting in Afghanistan, foreign affairs have merited hardly a mention in the present electoral contest. When the party leaders are pressed on questions of "abroad", their shared strategic assumption is that the world will continue to turn pretty much as before.
The reality is otherwise. Robin Niblett, the director of Chatham House, is leading a comprehensive review of UK foreign policy options for the London foreign policy think-tank. Whatever the course of domestic politics, he says, "the changes taking place beyond Britain's shores will have profound implications for the country's prosperity and security".
Britain's next government, he adds, will face changes and pressures that include "the accelerating shift from west to east in the global balance of economic power, the inevitable deep cuts that will need to be made in Britain's military and diplomatic capabilities, a more ambivalent relationship with the US and uncertainty about the European Union's future international influence and capacities".
The next few years, in short, are set to prove a watershed for a nation that has grown used to punching above its weight in foreign policy.