When earlier this year, as part of a small private delegation, I met General Secretary Mikhail S. Gorbachev, he asked why I was so opposed to the Reykjavik formula -- key parts of which are now embodied in the Intermediate Nuclear Forces agreement about to be examined by the Senate. I told him that some Americans want agreements virtually for their own sake regardless of content; others oppose any agreement regardless of content. I belong to a third group, I said, that wants agreements if they really make a difference. Gorbachev began to push me on what I thought did make a difference, but he soon decided that it was unwise to explore, before witnesses, alternatives to a formula so promising for Soviet strategy as Reykjavik, and he turned to other subjects.

This article serves as a substitute for that aborted discussion about what makes a difference. If I had had the opportunity or the presence of mind, I might have said something like this:

''The nuclear superpowers concentrate on their reciprocal nuclear arrangements, seemingly oblivious that new power centers are emerging which, by the next century, are certain to reduce superpower predominance. Historically such a process has always produced years, sometimes decades, of political tensions. And history leaves little doubt about two other propositions: 1) Almost all wars have been caused by the failure to solve central political issues, not by arms races. 2) Conventional deterrence rarely works. Unfortunately, Reykjavik devalued the nuclear deterrent by producing agreements on the zero option on medium-range missiles, and on the totally unrealistic objective to abolish all nuclear weapons with the destruction of strategic missiles as a first step. Thus, the resolution of political conflicts grows correspondingly more urgent because it is unlikely that they can be contained by conventional deterrence alone. True, lip service is being paid to the objective of a political dialogue. But it has yet to receive appropriate high-level attention or negotiating priority.

''The outline of the world by the year 2000 is already apparent:

"Japan will become an important military power as its formal military expenditures creep toward 2 percent of gross national product, and expenditures on matters relevant to military capacity such as space research will put Japan well above 2 percent.

"China's economic reforms will proportionately increase its military potential and its weight in international affairs.

"India, already the most powerful country in South Asia, will continue to grow. It has shown every readiness to use power to advance national interest.

"Western Europe will increase its cohesion in the political, economic and military areas -- in part as a reaction to being a bystander while decisions about its security are being made by the two superpowers.

"The developing countries are certain to accelerate their pressures for a more important role in world affairs and for a greater share in global economic well-being.

''Never have so many changes occurred simultaneously in so many different parts of the world. In the past, the emergence of even one new power center has led to decades of turmoil as the balance of power was adjusted -- usually by war -- to the emerging reality. If the Soviet Union continues to fuel all conflicts -- from the Persian Gulf to Angola, from Southeast Asia to Nicaragua -- by weapons sales and intelligence and political support to its friends, some crisis inevitably will get out of control with cataclysmic consequences. A war between the United States and the Soviet Union would inevitably hasten the relative decline of both countries and the shift of the world's center of gravity to other areas.''

I do not know how Gorbachev would have reacted to such a disquisition. I am convinced that arguments based on the balance of power would have more meaning for a leader whose entire career has been in the Communist Party with its emphasis on the decisive role of ''objective factors'' than do sentimental invocations of personal relationships or invitations to see the ''realities'' of American life, including back-yard swimming pools.

At any rate, such a dialogue has not occurred. The most conservative U.S. administration of the postwar era is preoccupied -- almost obsessed -- with arms control and personal appeals to the Soviet leadership. Agreements are called historic because they abolish two categories of nuclear weapons but are then schizophrenically justified as safe because all necessary military missions can be performed by the remaining nuclear arsenal. Agreement has become its own reward.

The euphoria of the Gorbachev visit may in retrospect appear as an escapism that dealt with symptoms, not causes. The underlying political crisis may in fact be accelerated by the gradual deterioration of America's leadership role and the danger that the Soviet Union may be tempted by the West's yearning for tranquillity, however temporary, to tip the global balance of power in its favor.

Technology was bound to reduce gradually America's nuclear superiority. Yet American decisions have accelerated the process before adjustments could be made. The combination of inferiority in conventional forces and -- at best -- parity in nuclear destructive power, coupled with the de facto abandonment of the Strategic Defense Initiative, will sooner or later demoralize allies that have relied on American military protection. Unless a conventional balance is restored, either by buildup or negotiation, conditions for Soviet blackmail will have been created in equal parts by arms policies and arms-control policies dominated by short-term domestic considerations. But the Soviet knowledge that economic conditions are likely to prevent an expensive conventional buildup weakens the Western bargaining position in any negotiation to reestablish a conventional equilibrium.

Gorbachev may well be sincere in seeking a respite; the internal situation in the Soviet Union in fact gives him few other options. But it is expecting too much for him to offer concessions that have not been asked and to refuse to take advantage of opportunities presented on a silver platter. The careful planners in the Kremlin surely understand the process of historical change outlined earlier. But they cannot fail to recognize that almost all emerging power centers are located on the Soviet borders. If that process succeeds, containment of Soviet expansionism could come about not primarily as a projection of American power but as a result of growing local strength and cohesion. The location of these new power centers makes them vulnerable to Soviet conventional strength, however, and current Western policy may tempt the Soviets to neutralize those burgeoning powers before they consolidate their strength.

Thus the Reykjavik proposals do make a difference. But rather than produce stability, they may over time wreck what has been built by bipartisan American efforts over 40 years. Whatever their stated purpose from the Soviet point of view, these schemes have a corollary benefit: They enhance the European sense of impotence and may tempt separate deals with Moscow, especially by the Federal Republic of Germany. The Soviets can then seek to wrest concessions from China before that country's economic progress makes it too formidable; Gorbachev's invitation for a summit with Beijing may be the first step in this direction. Such an outcome, in turn, would leave Japan with little choice but to adjust to the region's dominant reality, relying on its unique social and political institutions to maintain its independence. Fortress America -- the dream of so many isolationists -- would have turned into Imprisoned America.

In short, the West's policies run the risk of increasing long-term perils while reducing its capacity to deal with them. All this will be compounded because too many in the democracies justify the present course by postulating a moral equivalence between East and West that removes any sense of danger or even perspective, especially from the younger generation. The ironic result is that it is Gorbachev, not Reagan, who gets credit for Western concessions.

Negotiations with the Soviet Union are important and necessary. Modern technology drives the superpowers toward coexistence; Gorbachev's personality coupled with Soviet internal difficulties may provide opportunities approaching that goal. But the process is neither automatic nor can it be based on personal relationships. It should reflect a hard analysis of long-term interests, including the following:

a) Glasnost and perestroika represent attempts to modernize the Soviet state. That is an internal Soviet matter relevant to the democracies only if accompanied by a change in Soviet foreign policy.

b) Any foreign policy change must be reflected in concrete negotiations on political issues. It should deal with areas of tensions and should address what measures are permissible and where. Under what conditions and where is the sending of arms or the conduct of intelligence activities to take place? More complex topics must also be included, such as how to prevent tensions before they occur. From that point of view, the potential Soviet withdrawal from Afghanistan would be more significant than any other negotiation.

c) The current nuclear arms control negotiations are too one-sided. No further step should be taken toward nuclear arms control unless it is linked with measures that reduce Soviet preponderance in conventional weapons.

d) Immediate attention must be given to the conventional balance. The numbers game of measuring conventional deterrence by the equality in manpower and equipment must be abandoned. It violates the most elementary lesson of history: victories are won not by total numbers but by the ability to concentrate force at the decisive point. A thoughtful concept is even more essential for negotiations regarding conventional arms control -- a much-neglected subject. If it is not dealt with soon, the upcoming negotiations will turn into another trap dominated by slogans and domestic politics. Soviet spokesmen are already promoting a trade of Soviet tanks for Western aircraft, another step along the road of leaving Europe under the nuclear gun while even further weakening America's ability to retaliate from Europe. That would be another step, too, on the road toward separating America and Europe.

e) The highest priority for U.S. policy must be to construct -- with its allies -- a definition of vital interests, to determine what is necessary to defend those interests and the appropriate negotiating positions to adopt with the Soviet Union.

Devising such a strategy is a difficult, subtle but manageable task. Given the relative economic positions of the two sides, it must be easier for the democracies to preserve the global balance of power than it is for the Soviet Union to upset it. It is a simple evasion for the democracies to permit themselves to be so mesmerized by the personality of a Soviet leader, however able and charming. They have all the means to take charge of their own future.