PARIS. — The Soviet Union has made a momentous return to great-power politics, whether its Iraq peace proposal fails or succeeds. The many months of Soviet retreat from Cold War, and accommodation to the United States, have come to an end. This reassertion of a Soviet interest in Mideastern and Islamic affairs is evidence of an intention to find advantage in how the Iraq crisis ends.
The Soviet plan (reportedly) offered Saddam Hussein's government and state a unilateral Soviet guarantee of survival in exchange for unconditional withdrawal from Kuwait, promising Soviet support for subsequent action on the Palestine question and the other issues that were part of the peace ''program'' Iraq proposed Friday.
If the United States and its allies turn the plan down while Iraq accepts, the United States is responsible for continuing the war. If both accept, Moscow takes the credit for ending the war and obtaining Iraq's withdrawal from Kuwait. The military pressures created by American action are overshadowed by the success of Soviet diplomatic intervention. As Iran has been associated with the negotiation of this solution, playing an ambiguous role from the start of the war, a new Soviet-Iraqi-Iranian troika seems to emerge in the Persian Gulf -- which the United States can scarcely welcome.
If the plan is rejected, it has nonetheless restored Moscow to its traditional position as patron of Palestinian and radical Arab nationalism, friend of those who identify Saddam Hussein's defiance of the United States and the U.N. coalition with a defiance of imperialism in a new guise.
The Soviet Union accomplishes this without diminishing its support for a reinvigorated United Nations, part of its post-glasnost course in international relations. In short, the Soviet Union ends up on all sides of this conflict. It wins, no matter who wins the war itself.
The plan also exploits to American disadvantage the unconfronted weakness in America's position, on the eve of a ground offensive in Kuwait. There are two grand battles in prospect. One, in Kuwait, is supposed to be won without prohibitive costs. The second, in Iraq, is politically complex and poses a considerably difficult military problem.
It must be understood that the Iraqi command itself distinguishes between defending Kuwait -- the ''19th province'' of Kuwait until last Friday -- and defending Iraq itself. The forces manning the defenses of Kuwait are not, for the most part, first-quality troops. Those are being withheld for the second battle, for Iraq. The forces in Kuwait are expendable. Their role is not to succeed, but to fail at the highest possible cost to the allies. After that, the war will become serious.
The coalition military command believes that if no major mistakes are made, the battle to liberate Kuwait can be completed rapidly and at acceptable levels of allied casualties. If the Soviet plan is rejected, we are soon to find out whether this assessment is correct.
Even if the allied campaign in Kuwait goes as foreseen (campaigns never go as foreseen; let us say that if it succeeds in its objectives), Washington and its allies will find themselves at the foot of a new escalation ladder, with new political and military thresholds to breach.
At that point the allied force divides on policy. No agreement has yet been reached on the objective of this war. Some in the alliance, and inside the American government itself, would stop the war when Kuwait has been freed. Others would consider the war a failure if Saddam Hussein and his government are not deposed and a new power balance established in the region. Israel believes this. It is quite possible that if the allies should stop with President Saddam still in power, Israel would intervene to finish him off.
The Soviet position, and that of many in the alliance as well, is that the U.N. mandate under which the allied force acts is limited to the liberation of Kuwait. They would argue that Saddam Hussein would then have been defeated, humiliated after all he has claimed, his country crippled by the allied bombings and his people bitterly punished for his ambitions -- and international justice would have been vindicated. There are many in Washington willing to leave it at that. The argument is going on right now in U.S. government and the press. However, once in a war, the American habit is to demand unconditional surrender.
It would be possible for the United States to win the battle of Kuwait, and lose the peace that follows by losing the political credit it now commands as organizer and leader of the U.N. coalition. It is possible that the war could change character at Iraq's frontier, with the grand alliance associating Muslim nations with North America and Europe to free Kuwait breaking up. The second stage of the war could then become a unilateral American (or Anglo-American) march on Baghdad -- with a possibility of Israeli intervention as well.
The Soviet Union has placed itself splendidly to exploit any outcome. Mikhail Gorbachev may be in desperate straits at home but he has not lost his touch in matters of international politics. His intervention in the Iraq crisis was perfectly timed and defined. Washington should not underestimate the Soviet capacity, and determination -- as in part a Muslim nation itself -- to have a major influence on what the Middle East becomes when this war finally is over.
William Pfaff writes on international affairs.