U.S. Expected to Emphasize Peace but Warn of Warfare : Summit: Bush intends to talk tough while putting a formal stamp on superpower cooperation, officials said.

The hastily called Helsinki summit will emphasize peaceable tactics for resolving the Persian Gulf crisis, but President Bush is expected to tell Soviet leader Mikhail S. Gorbachev that if diplomatic and economic sanctions fail, the United States is prepared to use military force to destroy Iraq’s vast war machine.

With the Soviets already uneasy about the possibility of U.S. military action against Iraq, that message from Bush at Sunday’s one-day summit could be the one discordant element in what is otherwise expected to be another demonstration of the harmony and cooperation that increasingly characterize relations between the nuclear superpowers.

Spokespersons for both countries said U.S.-Soviet cooperation in trying to resolve the gulf crisis will be the major topic on the agenda. Though other issues will also be discussed, Administration officials played down the possibility of major action on arms control--and suggested that Bush and Gorbachev may not be able to keep their pledge of agreement by year’s end on a treaty reducing conventional forces in Europe.

A major summit objective for Bush, according to a senior government official, is to “validate and put the formal stamp” on U.S.-Soviet cooperation in the gulf and on continuing superpower relations “in a visible, political way.”

The summit marks the first time the United States and the Soviet Union have sought to address a global crisis jointly since World War II, and one senior U.S. official said, “This could be a watershed in how we address regional conflicts in the future.”

A senior Administration official said Friday that Bush and Gorbachev would be “looking down the road to discuss how each one sees events unfolding and what alternatives might be available to deal with the different ways in which the situation could be unfolding.”

Asked whether the United States would be seeking explicit Soviet approval for future U.S. actions, the senior official said: “Of course (Bush) will be interested in knowing what President Gorbachev’s perspectives are on all of the aspects of it.”

A Soviet spokesman indicated that Gorbachev is prepared to propose that Washington agree to placing a U.N. peacekeeping force in the Persian Gulf that would lessen the possibility of a unilateral U.S. military strike, but Administration officials have made it clear that they oppose such a step--at least for now.

Officially, U.S. officials say they are unwilling to experiment with an untested U.N. command structure during a major crisis. Privately, they acknowledge that the United States is not now prepared to surrender its freedom of operations to an international command.

A military strike is not part of Bush’s publicly stated policy. But senior government officials involved in planning Persian Gulf strategy say it may become the only alternative if sanctions fail, Iraq continues to occupy Kuwait and its vast military machine continues to pose a threat to Saudi Arabia.

The only question, these officials say, is how long the United States should wait to determine whether sanctions are likely to work or fail.

Although some officials have suggested that an assessment of the sanctions’ success or failure could come as early as next month, when the powerful U.S. military buildup in Saudi Arabia will near completion, others have said the effectiveness of the sanctions may not be measurable for six months or longer.

“I’m not aware of any specific time limits one way or the other,” one official said. “We’ll be looking at how the sanctions work and drawing conclusions periodically. If they appear to be working, we probably will stick with them, but if they don’t, obviously we’ll consider the military alternative.”

Another official involved in Persian Gulf strategy, declaring there is no “deadline” for considering military options, said that analysts are assessing sanctions almost daily and that they are “working very well” at this time.

But the official said that, no matter how well the embargo works, it would be “difficult, if not impossible” for the United States to achieve its objectives through such sanctions alone. Bush has said U.S. goals are to force the unconditional withdrawal of Iraqi forces from Kuwait; restore Kuwait’s legitimate government; assure the stability of Saudi Arabia and the Persian Gulf, and protect American citizens.

The Soviets voted with the United States on U.N. Security Council resolutions condemning Iraq’s Aug. 2 invasion of Kuwait, implementing sanctions against Baghdad and authorizing the use of military means to enforce the sanctions. But Moscow has cautioned against any offensive action by American forces against Iraq.

“I don’t think that U.S. troops would be well advised to take some unilateral, one-sided punitive action,” Soviet Foreign Minister Eduard A. Shevardnadze said.

The Soviets’ proposed U.N. peacekeeping force for the gulf would include Soviet troops under a joint command, and that command would include Soviet generals.

Gennady I. Gerasimov, spokesman for the Soviet Foreign Ministry, said the Security Council should revive Article 47 of the U.N. Charter, which provides for a military staff committee made up of the five permanent council members--the United States, the Soviet Union, China, Britain and France.

“This committee will have military forces at its disposal,” he said. “And of course we will be ready to participate.”

Asked whether the proposal was meant to make sure that Soviet generals were in command of Soviet troops to prevent unilateral military action by the United States, Gerasimov said, “Yes.”

At the Helsinki summit, Bush is also expected to press Gorbachev for an early withdrawal of 193 military advisers from Iraq.

Although a senior government official said the presence of the advisers in Iraq should not be considered a major military factor, it has become a nettlesome political issue. Members of Congress returning to Washington this week after the August recess have criticized the Soviets for keeping the advisers in Iraq in the aftermath of the invasion of Kuwait.

Times staff writer Douglas Jehl contributed to this report.