I have a sinking feeling that no matter how the Gulf crisis turns out, it marks the United States' swan song as the great world superpower. By this, I do not mean that we will retire from the global stage but rather that our efforts to exert leadership -- to keep order and to project a vision for the world -- will become less frequent and ambitious. The reasons are simple: Americans increasingly resent our superpower role, and Europe and Japan decreasingly support it.

Let's start with our "allies." Their behavior in the Gulf crisis has been almost shameful. True, they boycotted Iraq and have talked tough. But talk is cheap. Excluding Britain, no European nation has made a major military commitment to Saudi Arabia. France is now raising its force from 6,000 to 10,000. The European and Japanese financial contributions have been modest and, more important, have had to be coaxed from them.

You might think they have no vital interests in the Gulf. But Europe and Japan depend more on imported oil than we do. And should Iraq emerge as a nuclear power, its missiles will be able to strike Europe and not (probably) the United States. The Gulf crisis presents a classic case of the "free rider" problem: Europe and Japan want the benefits of a stable world order without bearing the costs.

By "costs," I mean something more important than merely footing the bill. I mean the ability to make hard political decisions -- steps that are potentially unpopular -- to bolster a world order that serves their interests. It is this capacity that Europe (Britain, again, excepted) and Japan lack, and their Persian Gulf performance symbolizes a wider failure.

Consider the recent collapse of the Uruguay Round of trade negotiations. The European Community caused the breakdown by its refusal to make meaningful changes in its Common Agricultural Policy, which heavily subsidizes food exports. Japan might have nudged the Europeans by renouncing its ban on rice imports. It didn't. Neither Europe nor Japan would take action opposed by its politically powerful farmers. As a result, the trading system faces a major crisis and the danger of rising protectionism.

These leadership lapses are not aberrations. Recently I attended a conference of European and U.S. journalists, academics and government officials. The Europeans left me with two strong impressions: (a) they are totally preoccupied with Europe's problems (German reunification, European integration, immigration from Eastern Europe and North Africa) and (b) they simply don't talk of "global responsibilities" and don't care that Americans expect more of them. The Japanese are equally self-interested.

There's a tendency to think America will always be there in the clutch -- just as it is in the Persian Gulf. Don't bet on it. President Bush belongs to the World War II generation, which believes instinctively in our duty to preserve world order. The instinct is fading. Vietnam left its scars. The Democratic Party is prone to protectionism and uneasy with military power. Almost every major Democratic politician -- stretching as far to the right as Sen. Sam Nunn -- has undercut Bush's Gulf policy by questioning the use of force.

What's also clear to many Americans is that being a superpower is neither fun nor profitable. Historically, one reward has been exploiting weaker nations. This was the style of 19th-century imperial Europe and Soviet Russia. By contrast, our postwar style has been to absorb extra costs (the military costs and the social costs of keeping our markets open) to create a world order that, we thought, would bring us peace and prosperity.

In return, we naturally expect the beneficiaries of the new order to shoulder some of the burdens required for its preservation. The underwhelming response of Europe and Japan feeds Americans' historical suspicions of foreigners. Why shouldn't we conclude that we're being played for patsies: that our soldiers are protecting their oil; that their commitment to open trade stops at concessions that help us?

Unavoidably, U.S. foreign policy is entering a period of major reappraisal. Since the 1940s, communism has been the great simplifier. It overwhelmed our isolationist impulses and made our foreign policy a great morality tale of good vs. evil. We might find the Europeans and Japanese selfish or petty, but we never doubted they shared with us basic values worth protecting. The Europeans and Japanese might chafe at specific U.S. policies and find American leaders self-righteous or simplistic. But they never doubted our good will or their dependence on our nuclear umbrella.

Now, communism's collapse has weakened these bonds. In an era of global economic competition, we are less sure of our foreign interests. Are Europe and Japan our allies or rivals? And our allies wonder whether they really need us anymore. Their concerns seem increasingly distant from America's. There is a confluence of doubts here and abroad. It bodes ill, precisely because all of us still have vital interests in common.

It is in our interest to stop Saddam Hussein from controlling 60 percent of all oil reserves or from acquiring nuclear weapons. We have an interest in preventing a collapse of world trade, protecting the global environment and averting chaos in Eastern Europe or the Soviet Union. Just because we cannot predict the exact consequences of these developments does not mean they would not hurt us or that we should be passive.

The trouble is that we may be unable to clarify post-cold-war goals or act on them. Our Persian Gulf policy is as much the result of past habit as of present conviction. Our allies' rhetoric about shared values rings hollow unless matched by shared sacrifice. If things go well in the Gulf -- if Saddam leaves Kuwait peacefully without concessions -- Americans' doubts and resentments about our world role will linger. But if things go badly, they will burst forth ferociously.