About a decade and a half ago certain scholars began to call attention to the importance of “soft power” in world affairs, which they defined as the capacity to win friends abroad and persuade other nations to agree to policies that you want. It was very different by nature from “hard power” — that is, military strength and economic muscle — but it was nonetheless real. Thus the crumbling USSR under Brezhnev was weakened by being culturally and ideologically unattractive to other peoples. By contrast, a US boasting lots of soft power — the English language, Hollywood, the Wall Street way of doing business, democracy, the Bretton Woods institutions — gained from this additional measure of power and influence.

Yet there has always been one feature to “soft power” that has made it less substantive than military capacity or economic resilience: You can lose it or gain it — or even regain it — very swiftly indeed. The Bush administration has been a spectacular example of how the US could rapidly destroy its attractiveness once it appeared bent on unilateralist, heavy-handed, neoconservative actions, and didn’t seem to care about world opinion. Little wonder, then, that outside the US there was such jubilation when Barack Obama was decisively voted in. Before the world begins to think Obama can walk on water, we ought perhaps to reflect on what the recovery of US attractiveness and soft power cannot do. Here, alas, we have to return to the horrid world of “hard” power: Economic reality and geopolitical reality.

Soft power cannot pay for foreign oil and gas, imported cars, electronic goods, kitchenware and children’s toys. Soft power cannot staunch General Motors’ global disintegration, just as it could not stop the collapse of Lehman Brothers. Soft power seems to have very little influence over the wildly fluctuating exchange value of the dollar: when the trade deficit worsens, so does the greenback; and when hedge funds pull back monies from Brazil and Canada the dollar rises, like a cork on the tide, at least for a while. If Asia’s appetite for Boeing’s planes falls away, no amount of Obama charm will stop that. More important still, if Asia decides it is too risky to continue buying American treasury bonds, then White House glamour will count for little. The international financial system is no longer as it was at Bretton Woods, when only one country could recreate the world’s trading and currency systems. There is a larger lesson from the recent desperate efforts by central bankers — in Britain, Germany, the European Bank, Japan, Switzerland — to shore up a few crucial banks, country by country. The lesson is that the US followed, reluctantly. It did not lead.

The same trend is evident at the IMF, yet another American institution slipping away from its founder’s half-century dominance. How the world turns. We have come back to a multipolar system, whether US neocons or liberal imperialists like it or not.

The same is true on the military-strategic playing fields. How exactly, one wonders, would revamped US soft power be applied to counter the assertiveness of an increasingly nationalistic Russia, smarting at its imperial collapse and intent on balancing the influence of the world hegemon? What can the president-elect’s undoubted charms do in the face of China and India’s remarkable maritime expansion, with their silent submarines, long-range rocketry and satellite capacity?