I think it was Madeleine Albright, former US secretary of state, who first called the United States the indispensable nation. The phrase, coined in those heady days after the collapse of Soviet-led communism, reflected America's unique capacity to project power just about anywhere in the world.

After more than a decade of relative decline the description still broadly holds. Even as the challenge from rising states obliges the US to abandon the hegemonic ambitions of the early years of George W. Bush's presidency, it remains the only power with real global reach.

A less noticed dimension to American power is coming into view as the international order falls into disrepair. Were a serious attempt to be made to refurbish the multilateral system, the US would be the linchpin. As it happens, though, it is also the nation best able to go it alone.

There is a striking paradox here: the player that stands at the centre of the present global system would have less to lose than the rest from its demise. More than any other the US, to adapt Albright's sobriquet, is the world's self-sufficient power.

American declinism has been much overdone. The US will remain the pre-eminent power — at the very least primus inter pares — for many decades to come. Economic size matters, but Britain's imperium survived more than half a century beyond its surrender of the top economic slot. Even if China's rise was to continue in a linear fashion — something that would defy all the experience of the past — it would be decades before it matched America's global might.

What is true is that, as Washington's will is increasingly contested, the US-led international system established after 1945 is cracking. The globalising world of the last decades of the 20th century is giving way to one in which states are turning inward.

The isolationism of Ron Paul in the Republican presidential primaries amplifies a tune heard pretty much everywhere around the world. The rising states of the east and south cherish narrow definitions of national interest, and resent the intrusions on sovereignty of a rules-based system. Even in the European Union, the home of post-modern integration, the euro crisis has sorely tested a long assumed merger of national and mutual interests. For its part, the US is retrenching. It has grown tired of wars and has been piling up deficits and debts. President Barack Obama has announced big cuts in the Pentagon's budget. America will be more sparing in its deployment of military might. Europe will have to look after itself and much of the greater Middle East will be left to itself. Resources are to be concentrated on sustaining America's Pacific primacy.

Transitional gains

As Washington steps back from the role of global policeman, US foreign policy is looking to its role as a convener of regional alliances and ad hoc coalitions of the willing. Europe has all but abandoned its global pretensions to the struggle to save the euro. The emerging multipolar world, in other words, is becoming less multilateral.

The big question for the coming decades is how far this process goes: to what extent does Hobbes triumph over Rawls as the competitive impulse takes over from the co-operative. The question then worth asking is who gains from such a transition — or, more accurately, who loses least?

For all its present problems, the US starts with the immense advantage of being the richest and most stable of the great powers. Geographically it is the most secure — unless one imagines it might one day be invaded by Mexico or Canada. It is rich in natural resources. New technology in oil and gas extraction has transformed the energy industry. The US is heading for self-sufficiency in energy and, by some accounts, could become a significant net exporter. Unfair as it might seem given its record on carbon emissions, it is much less vulnerable than say, China or India, to the depredations of climate change.

Some of the other advantages were set out recently in a paper prepared by Uri Dadush of the Carnegie Endowment as part of the US National Intelligence Council's Global Trends 2030 project. To take a few: America's high per capita income reflects high productivity, the single best measure of competitiveness; with 5 per cent of the world's population, the US accounts for 28 per cent of all patent applications; it has 40 per cent of the world's top universities; an open, innovative and flexible society leaves it uniquely placed to benefit from technological advances. Oh, and it has a great demographic profile.

All this before we get to US military power. Last year China caused quite a stir when it launched its first aircraft carrier — minus any jets to sit on its flight deck. America currently operates 11 carrier groups. Next on the list is Italy — with two. None of the above suggests that the US would gain from retreating into its continental fortress. To the contrary, its economy has become progressively more integrated into the global system; and, for the moment, it relies on foreigners to finance its consumption. A world of everyone for themselves would leave everyone poorer.

There is, though, a second part to the paradox. China would be the really big loser. It starts out still relatively poor, is geographically insecure and is short of almost any natural resource you can think off. Its economy relies on western markets. It needs a stable, open international system. It's an intriguing thought: how long before China emerges as the new champion of the multilateral order?

— Financial Times