THE RECENT ATTACK on the USS Stark has again focused attention on a question that has haunted American foreign policy since the Vietnam War: What military role should the United States play in the world? And what is the proper role of NATO?

In thinking about these issues, we should bear in mind three considerations:

The Persian Gulf is a crucial strategic area for the United States and we should take whatever steps are necessary to maintain our influence there. We cannot accept another major strategic reversal in that region, after the loss of Iran and the Soviet invasion of Afghanistan.

Our long-term involvement in the Persian Gulf will require some restructuring of our military forces away from the current overconcentration on the defense of Europe.

This reallocation of U.S. military resources need not weaken -- and could, in fact, strengthen -- the NATO alliance. To keep NATO strong, we should focus arms-control negotiations on the conventional weapons that are most threatening to Europe, proposing specifically the creation of a "tank-free zone" in Central Europe.

My argument is based on the judgment that the American-Soviet conflict is an historical rivalry that will endure for as long as we live. In this enduring American-Soviet contest, there are three central strategic fronts: Europe, the Far East, and southwest Asia.

Access to Persian Gulf oil reserves, which contain two-thirds of the free world's proven reserves, is the principal stake in southwest Asia. It is estimated that in 1995 the free world will receive between 30 and45 percent of its oil from the Persian Gulf states. If the Soviet Union were ever to achieve predominance over southwest Asia, Moscow would be able to exert tremendous leverage over our allies in Western Europe and Japan.

Consequently, the United States has no choice but to stand firm against any challenges in the defense of Western interests in the Persian Gulf. Taking the advice of some senators and congressmen who advise an American pullout from the Persian Gulf would mean that in a mere 10 years the U.S. position in that region would have collapsed. Ten years ago, the Persian Gulf was sealed off by a pro-Western defense perimeter involving Turkey, Iran and Pakistan, protected by the buffer zone of Afghanistan. The United States then lost its position in Iran, and shortly thereafter the Soviet Union invaded and occupied Afghanistan. Today, both Iran and Pakistan are in potential jeopardy. A U.S. pullout from the Gulf would demonstrate that Khomeini and his fellow thugs are now in control of the PersianGulf -- a strategic defeat 10 times worse than the loss of Iran.

The major beneficiary of a U.S. retreat would be the Soviet Union. Iranian control of the Gulf would at best be a transitional phase, to be followed by the expansion of Soviet influence, especially as American presence receded. One can only speculate on the political stampede that U. S. failure to act would generate in the weak and vulnerable Persian Gulf states.

In an ideal world, U.S. forces patrolling the Persian Gulf would be joined by French, British, Italian, Belgian and Dutch forces, all financed by Japan. That would be a perfect solution. But if that is not possible, it does not necessarily follow that the United States should do nothing. We must recognize that the United States holds the status of a world power, and our allies are simply regional powers.

The United States must do whatever is necessary to assert Western interests in the Persian Gulf -- alone, if necessary. If Iran strikes American forces engaged in protecting third-party shipping in the Gulf, the United States should retaliate against Iranian military facilities and do it in a way that will be militarily decisive. We have the power to do so from our aircraft carrier task forces, and we can also deploy B52s in Diego Garcia for a more devastating attack on key Iranian facilities, if needed.

We must also look at the overall allocation of American defense resources around the world. It should by now be clear, especially given NATO's recent outright rejection of a multilateral effort to patrol the Persian Gulf, that NATO has become exclusively a regional alliance. It is certainly not a global alliance. Since NATO countries refuse to play a role in defending Western interests in distant regions, we cannot avoid the conclusion that the United States must begin to undertake a reallocation of its defense resources.

In the needed restructuring of the U.S. defense effort, the United States must enhance its capability to fight in areas where it cannot permanently station forces of its own. That means three things: the United States will have to increase its airlift and sealift capability; it will have to create additional light forces, rather than heavy forces deployed in a single region and usable mainly in that region; and it will have to tell the West European countries to assume greater responsibility for their own defense -- which is something they clearly have the economic capacity to do.

The United States should undertake a gradually-phased redeployment of about 100,000 of the 350,000 troops from Europe. This should not be presented as a punitive measure, but as a gradual accommodation to strategic realities. At present, we are least prepared to defend our interests in the region in which a challenge is most likely, and most prepared in the region in which a direct military challenge is least likely -- and in which our allies have the greatest capacity to do more for themselves.

Claims that this would induce a rush toward neutralism by our Western European allies are not credible. It is hardly an expression of confidence in our allies to assert that a readjustment of U.S. troop levels in Europe will prompt them to commit political suicide. In fact, the level of our forces in Western Europe has oscillated greatly over NATO's 44-year history with no clear relationship to the level of either U.S.-Soviet tension or Western European "neutralism.".

The Defense Department's claim that a partial pullout from Europe would, in fact, be costly is also specious. First of all, the point is not to save money but to spend our money in a way that is suited to meeting likely challenges. Moreover, if reductions are phased in over time, integrated into the regular process of troop rotation, and coupled with conversion of heavy divisions into light forces, the process will generate the savings needed to increase air- and sea-lift capacity.

Such a restructuring of U.S. global deployments would be in keeping with basic trends in Europe. Increasingly, we have witnessed -- and will witness -- a gradual dilution of Soviet control over Eastern Europe and some gradual lessening of Western European dependence on the United States. This might even lead eventually to the revival of a genuine reassociation of the two halves of Europe. We should welcome such a movement away from a Yalta division of Europe.

In concrete terms, this change could mean the emergence in time of special arrangements, both political and security-related, regarding Central Europe. Such arrangements could include mutual thinning out of forces and introduction of comprehensive confidence-building measures. This process would help to end the artificial division of Europe, thereby diluting Soviet control and diminishing the direct Soviet conventional threat to the free countries of Western Europe.

Arms-control measures could be helpful in promoting this new reality. To be sure, it is likely that in the foreseeable future the Soviets will step up their efforts to advance the denuclearization of Western Europe. We must be vigilant and ready to rebuff such efforts. The best way to do so is through political preemption -- that is, by formulating proposals that deflect the Soviet effort and focus attention on those weapons in Central Europe that are in fact most threatening to peace.

The biggest threat to NATO is the enormous Soviet preponderance in main battle tanks, the weapons most suitable for a conventional attack on Western Europe. Since the Soviets are likely to propose further reductions in battlefield nuclear weapons soon, NATO should step forward now with a proposal linking any such reduction in battlefield nuclear weapons to a dramatic cut in the number of main battle tanks on the Central European front. A 50 percent reduction in their number, especially given NATO's relative strength in anti-tank weapons, would be a significant step in reducing the Soviet capacity for a major conventional offensive.

Better still, the West could propose that several NATO and Warsaw Pact countries in Central Europe, on both sides of the so-called central front line, be included in a "tank-free zone."

The removal of all Soviet tanks to the Soviet Union would greatly enhance military stability in the heart of Europe. This is particularly important now that the Soviet Union has equipped many of its most modern tanks with reactive armor, thus rendering many western anti-tank weapons ineffective. With a "tank-free" zone in place, any attempt to reintroduce surreptitiously a large number of tanks into the area would be subject to relatively easy detection and would provide significant warning time. Last but not least, a dramatic proposal for a tank-free zone in Central Europe -- embracing West Germany and Benelux on the NATO side, and East Germany, Poland, Czechoslovakia and Hungary on the Warsaw Pact side -- would be likely to gain public support in Western Europe.

We must not stay forever wedded to a conception of NATO as a global alliance based on geostrategic assumptions rooted in the 1950s. We need to reconfigure our world-wide military deployments. If we do so, we will be better able to meet the most likely threats, not only to American interests, but also to those of our allies in Western Europe and Japan. NATO will be all the stronger as a result, for it will be grounded on realistic expectations and will increasingly reflect the true interest of Western Europe as such. Our alliance is healthy, but health means creative and vigorous changes.

To conclude, we must respond to challenges to our interests with whatever force is necessary to prevail decisively, in Europe or the Persian Gulf. Contrary to the views of some on Capitol Hill and the military establishment, the lesson we should draw from Vietnam is not that we should avoid military engagements. Rather, we should draw these two lessons:

First, we should become involved militarily only when we have unambiguously major interests at stake -- as we do in the Persian Gulf. Second, if we become engaged, we must act with decisive power to achieve deliberately defined military and political objectives.

Zbigniew Brzezinski was national security adviser during the Carter administration. His latest book is "Game Plan." This article is adapted from a speech he gave yesterday at West Point.