PARIS -- Europeanand American officials are increasingly convinced that the Soviet Union will endorse military action against Iraq's occupation army in Kuwait if the United States seeks approval from the United Nations Security Council. The threat of war in the Middle East has knit the new Soviet-American partnership together more tightly instead of unraveling it as pessimists predicted at the outset of the crisis.

The Persian Gulf crisis is a practical testing ground for the seismic changes in East-West relations of the past 12 months. Stopping Iraq has become the second act in the great drama that began with the collapse of the Iron Curtain and communism. The third act will center on the creation of the new international order that President Bush and Soviet leader Mikhail Gorbachev have blessed.

U.S.-Soviet understanding on the need to force Iraq out of Kuwait is in fact a vital component of a post-Cold War system of international behavior. Instead of jeopardizing the new order, a Soviet-supported, U.S.-led military retaliation against Iraq's aggression can become a building block for an effort to make the United Nations and its institutions work as they were intended to before the Cold War made them hollow shells.

Gorbachev would understandably prefer to avoid an unpredictable war so close to Soviet borders. But the Soviet political leadership sees its fate irrevocably bound to the West. Gorbachev & Co. have accepted that they have more to gain than to lose from a U.S. success in the Gulf, through sanctions or by force. Buoyed by the cooperation of the five permanent members of the Security Council, Bush will decide in the next 30 to 60 days whether to seek U.N. authority to use force in Kuwait, U.S. and European diplomats think.

Moscow has strong reasons of its own, beyond the Western-help factor, for wanting to see the Iraqis denied a victory through aggression. The Soviets must fear that such an outcome would have a devastating impact on Iran, Afghanistan and other Islamic nations near the Soviet Union's frontiers and thus on the Moslem populations of the Soviet Union. "If it comes to shooting, the United States will be fighting our fight also," a Soviet academic told a small group of Americans and Europeans recently.

Soviet acceptance that it is likely to take force to get Iraq to give up Kuwait hardened after Gorbachev envoy Yevgeny Primakov paid a visit to Baghdad earlier this month. Despite the vague optimism Primakov voiced publicly in Baghdad after seeing Iraqi dictator Saddam Hussein, Soviet officials have said in private diplomatic briefings that Saddam let no sign slip that he was ready to consider withdrawal from Kuwait.

Primakov concluded that Saddam's obsession with keeping his whereabouts and movements an absolute secret has effectively isolated Saddam from information about the extent and effect of the international sanctions imposed on Iraq. "Primakov's trip suggests that Saddam does not know he is losing and does not believe it if anyone else tries to tell him, as the Soviets did," said a Western diplomat. "Moscow may now doubt that sanctions can do the job in time."

Saddam was also truculent about Primakov's effort to withdraw the majority of the 5,000 Soviet civilian technicians working on contract in Iraq. Saddam agreed to allow those with less than a year remaining on their contracts -- about one-third of the total -- to leave soon. But he would not discuss the remaining 3,500 technicians, who may be slipping into the hostage category.

The trip was an important one for Soviet policy and for Primakov, the portly, canny Middle East expert whose name has been mentioned in Moscow as a likely foreign minister if Gorbachev makes Eduard Shevardnadze his prime minister. Shevardnadze's stunning speech to the United Nations in which he warned that the United Nations might soon use force to free Kuwait struck some diplomats there as a valedictory. One Western envoy reports that Primakov was the only aide sitting in with Gorbachev in their recent meeting.

The Persian Gulf crisis has proved many existing expectations about U.S.-Soviet relations to be out of date. Those looking for reasons to avoid the use of U.S. force against Iraq cannot rely on warning of the consequences on superpower relations. The Gorbachev-Shevardnadze team has shown they will support a just war, even if it is led by American resolve and power.

And those of us who thought that trying to involve the United Nations in forcing Iraq out of Kuwait would be nothing more than a pretext for tying President Bush's hands have also been shown how the world has changed. The constructive Soviet attitude, and a Chinese willingness to go along with collective action in hopes of getting sanctions against Beijing lifted, offer Bush an undreamed of chance at getting U.N. authority and commitment to stop the first serious post-Cold War act of aggression in its tracks.

That prospect appears to justify the time and effort Bush has put into working so closely with the other four permanent members of the Security Council. But the United Nations has to remain a means to the important ends of ending Iraqi aggression. What must not be lost sight of is that making Saddam pay for this aggression is the only way a new international order can be brought into being.