SEOUL, South Korea

It is very useful to come to Asia to be reminded about America’s standing in the world these days. For all the talk in recent years about America’s inevitable decline, all eyes are not now on Tokyo, Beijing, Brussels or Moscow - nor on any other pretenders to the world heavyweight crown. All eyes are on Washington to pull the world out of its economic tailspin. At no time in the last 50 years have we ever felt weaker, and at no time in the last 50 years has the world ever seen us as more important.

While it is true that since the end of the cold war global leaders and intellectuals often complained about a world of too much American power, one doesn’t hear much of that grumbling today when most people recognize that only an economically revitalized America has the power to prevent the world economy from going into a global depression. It was always easy to complain about a world of too much American power as long as you didn’t have to live in a world of too little American power. And right now, that is the danger: a world of too little American power.

Somewhere in the back of their minds, a lot of people seem to be realizing that the alternative to a U.S.-dominated world is not a world dominated by someone else or someone better. It is a leaderless world. Neither Russia nor China has the will or the way to provide the global public goods that America - at its best - consistently has. The European Union right now is so split that it cannot even agree on an effective stimulus package.

No wonder then that even though this economic crisis began in America, with American bad borrowing and bad lending practices, people have nevertheless fled to the U.S. dollar. Case in point: South Korea’s currency has lost roughly 40 percent against the dollar in just the last six months.

“No other country can substitute for the U.S.,”a senior Korean official remarked to me.“The U.S. is still Number 1 in military, Number 1 in economy, Number 1 in promoting human rights and Number 1 in idealism. Only the U.S. can lead the world. No other country can. China can’t. The E.U. is too divided, and Europe is militarily far behind the U.S. So it is only the United States... We have never had a more unipolar world than we have today.”

Yes, many Asians resent the fact that Americans scolded them about their banking crisis in the 1990s, and now we’ve made many of the same mistakes. But that doesn’t last long. In random conversations here in Seoul with Korean and Asian thinkers, journalists and business executives, I found people really worried: Could it be, they ask, that the Americans don’t know what they are doing, or, worse, that they know what they are doing but the problem is just so much bigger than anything we’ve ever seen?

This is a region where Western brands carry great weight, and for people to see giant U.S. financial brands like Citigroup and A.I.G. teetering is deeply unnerving.

The big trading nations, like South THOMAS L. FRIEDMAN Paging Uncle Sam MARY ALTAFFER/ASSOCIATED PRESS As the world’s financial crisis continues to deepen, some nations are worried that the United States will succumb to economic protectionism. Korea, are particularly nervous that America will succumb to economic protectionism, which would undermine the global trading system.

“There is no one who can replace America. Without American leadership, there is no leadership,”said Lee Hong-koo, South Korea’s former ambassador to Washington.“That puts a tremendous burden on the American people to do something positive. You can’t be tempted by the usual nationalism. When things don’t go well, most people become nationalistic. And in the economic world, that is protectionism... We are pleased to see President Obama is not doing that. Americans, as a people, should realize how many hopes and expectations other people are putting on their shoulders.”

And that’s just on economics. President Obama’s first big security test could come here - and soon. North Korea has gotten crazier than ever; it has been made even poorer by the global economic crisis and by the withdrawal of aid by the new South Korean government. Now the North is threatening to test one of its Taepodong-2 long-range missiles, which may have the capacity to hit Hawaii, Alaska or beyond.

The North last tried such a test in 2006, but the rocket exploded 40 seconds after its launch. If the North does test such an intercontinental ballistic missile again, American forces will have to consider blowing it up on the launch pad or shooting it out of the sky. We never should have allowed the North to get a nuclear warhead; we certainly don’t want it testing a long-range missile that could deliver that nuclear warhead to our shores, or anywhere else.

Never more inward-looking, never more in demand: that’s America today. This moment recalls a point raised by the Johns Hopkins University foreign policy expert Michael Mandelbaum in his book,“The Case for Goliath.”When it comes to the way other countries view America’s pre-eminent role in the world, he wrote,“whatever its life span, three things can be safely predicted: they will not pay for it; they will continue to criticize it; and they will miss it when it is gone.”