The long neglected and seldom-used peacemaking machinery of the United Nations was cranked up and set in motion over the past week and, surprise, it worked - at least initially. Iraq, one of the two belligerents in the world's largest, longest, and bloodiest current war, announced that it would honor the cease-fire ordered by the UN Security Council until or unless the other belligerent, Iran, broke it. Iran said the resolution was unfair, but up to this writing neither side had totally rejected it.
Although few outside observers believe that a cease-fire will last very long, by press time there had been no reported attacks by either side in Gulf waters since the Security Council had unanimously called for the cease-fire Monday.
It was under cover of this ``truce'' that President Reagan's latest use of American military power in far-off places began. Two tankers owned by Kuwait, but with American captains and flying the American flag, hoisted anchor and sailed through the Strait of Hormuz 600 miles to Kuwait.
But this operation - unlike the UN vote - was not begun in concert with the Soviets. Soviet leader Mikhail Gorbachev had written a letter to Mr. Reagan proposing talks about the war in the Gulf and ways and means of bringing that war to an end. The White House showed little early enthusiasm for any idea of collaboration with the Soviets.
Yet the interesting fact remains that when the United States and the Soviet Union joined in supporting a resolution in the Security Council, it worked (at least momentarily). The vote was unanimous. Even China, which has tended to side with Iran, voted for the resolution.
The resolution had some effect on the belligerents, or appeared to do so.
It is of course possible that there would have been a temporary lull in the fighting without any UN resolution. There is war weariness on both sides.
The tankers are being escorted by US naval vessels. The US has expanded its naval strength in the Gulf. This is a display of US military power, the fourth such during the Reagan presidency: He sent US Marines to Lebanon in 1983; ordered the invasion of Grenada in October that year; and bombed Libya in April 1986.
The Soviets are playing their hand in this affair in lower key. They have loaned three of their tankers to the Kuwaitis. They maintain a small naval patrol in the Gulf. They said that they will not increase their naval forces in the Gulf. They protested the increase in US forces.
The Soviets joined in the Security Council resolution, but took an ambiguous position on the question of whether they would join in an embargo against Iran if Iran violates the truce.
To the outside world, the appearance is unavoidable that Mr. Reagan has used the tanker war in the Gulf as an excuse to increase US military presence there. Mr. Gorbachev has achieved the appearance of the opposite. It is a plus score for Mr. Gorbachev in European and Middle Eastern eyes.
The sum total of the past week's events constitutes a reminder that there still is an organization called the UN in New York, and that it does have machinery designed to help shorten wars and keep the peace.
It has been a long time since much attention has been paid to it. Its possible usefulness has been frustrated by the rivalry between the US and Soviets. The usual story from the UN has long been one of Moscow putting a veto on anything Washington proposes, and vice versa.
A unanimous affirmative vote in the UN is news. It calls attention to something long overlooked in Washington - that there are some situations in the world where US and Soviet interests are similar.
Today both nations, for their various reasons, would like to see an end to the Iran-Iraq war. Progress could probably be made if the two would coordinate their policies. It is not beyond the realm of the conceivable that serious joint effort could bring that war to an end.
But if there was a chance in the Gulf over the last two weeks to explore the possibilities of collaboration with Mr. Gorbachev in one area where interests are similar, Mr. Reagan missed it. We cannot know whether this was because his mind is concentrated on keeping the Soviets out of the Gulf or on what Rear Adm. John Poindexter did, or did not, tell the Congressional committees investigating the Iran-contra affair.