But Europe is discovering that it is hungry for all the attention it can get, even from a politically distracted and economically weakened United States. On Friday, Timothy F. Geithner, the secretary of the Treasury, is to attend a meeting of European finance ministers in Wroclaw, Poland, at the Europeans’ invitation. That will be his second trip across the Atlantic in just seven days — Mr. Geithner was in Marseille at the beginning of the week, where he told the Group of 7 meeting of finance ministers and central bankers that Europeans needed to “act more forcefully” to address the crisis.

“It is so interesting that Geithner is going to the Ecofin meeting,” said Jim O’Neill, chairman of Goldman Sachs Asset Management. “There is nobody inside the euro area who has the leadership ability to solve it. So it might be that it is convenient for them to have a superpower appear as the great savior.”

A muscular United States is being missed on the world’s battlefields, too. Canada is one of the world’s most ardent multilateralists, for reasons of geopolitical necessity as well as cultural inclination, and Canadians have more cause than any other nationality to suffer from little-brother syndrome when it comes to the behemoth with whom they share a continent.

But in the testing ground of Afghanistan, Canadian soldiers came to love Big Brother. “Our own guys learned in Afghanistan that if you’ve got American capabilities behind you, you’ve got the best there is, but you can’t rely on NATO the way you can on the United States,” said David Bercuson, head of the Center for Military and Strategic Studies at the University of Calgary. “NATO is nothing without the United States. Our military discovered that.”

“The Europeans talked a very good game about setting up a European defense community. But now, with the deep budget cuts coming, the notion Europe would evolve into any significant military power seems further away than it was 10 years ago,” Mr. Bercuson said.

Both in Kandahar and in Wroclaw we are learning the unpleasant realities of living in what Ian Bremmer and Nouriel Roubini have dubbed “a G-Zero world.” As they argued in an essay in Foreign Affairs magazine: “We are now living in a G-Zero world, one in which no single country or bloc of countries has the political and economic leverage — or the will — to drive a truly international agenda. The result will be intensified conflict on the international stage over vitally important issues.”

Michael Ignatieff, the writer and former leader of the Liberal Party of Canada, said we shouldn’t waste our time debating whether the G-Zero world is a good thing. The point is that “this long transition to a world which is not run from Washington” is a reality, and one which we need to figure out how to adapt to fast. “The fact is that America is being forced to step back from certain tables — so the rest of the world needs to step up,” Mr. Ignatieff said.