It would be ironic if, by the law of unintended consequences, the Gulf crisis ends where it began -- with revolutionary Iran, the most powerful state in the Middle East, threatening Arabs and Israelis alike with its militant pietism.

Indeed, once the genies of war are let loose, it is possible to imagine a range of unintended consequences: the overthrow of moderate regimes in Egypt and Jordan by Islamic radicals, multiplying the vulnerability of Israel; the collapse of the fragile sheikdoms of the Gulf, sending the price of oil soaring for the next decade; a quixotic uprising of Kurds, shaking the regimes not just in Iraq but in Syria, Turkey and Iran.

Out of the mix of possible consequences, however, the greatest likelihood is an abrupt end to the equilibrium on the Iraq-Iran border, which was Saddam Hussein's gift -- Gen. H. Norman Schwartzkopf, U.S. commander in the Gulf, said as much in a recent interview in The New York Times -- to international stability.

A decade ago, the Middle East was in serious jeopardy from the legions of the Ayatollah Khomeini, bent on spreading their Shiite fundamentalist faith into the Arab world. Iraq's Shiites, a majority of the population, were tipping to their side. So were strong Shiite minorities in Saudi Arabia and Kuwait.

Historians may debate whether Saddam committed gratuitous aggression or was provoked into initiating war, but the fact is that he took on Khomeini, fused his own deeply heterogeneous people into a nation with a single purpose and fought the fundamentalist revolution to a dead halt.

The Iraqis did not wage a pretty war. Outnumbered three to one in population, they enjoyed greater firepower and used poison gas to win battles when they had to, though military experts generally agree that gas was not the key to their ultimate victory. Mostly, they won by digging in and inflicting heavier losses than they took, going on the offensive only when the Iranians were badly weakened by the attrition of their manpower.

It seemed obvious as the war approached an end that Iraq's battle-hardened army of a million men was likely to be a loose cannon in the region once it had no enemy. Rather wisely, the United States made serious efforts at that juncture to overcome the animosity that had long marked its relations and to reach a rapprochement that might contain a restless Iraq.

But dealing with a brutal, dictatorial regime that is insensitive to international public opinion was not easy. Critics glibly assert that the State Department did too much to accommodate Saddam Hussein. The real question, I believe, was whether we did enough to bring him into a system of international order.

We know Saddam is an unsophisticated, insular man who yearns for respect from other world leaders. He believed he had earned it by his triumph over Iran, and perhaps he had. Would it have made a difference if he had been invited to Washington or Paris to take a few bows? I suspect it would, but after he gassed his own Kurds -- insurgents, but Iraqi citizens -- no Western head of state could have received him on an official visit. And so the scenario of the loose cannon came to pass.

It alighted on Kuwait, for reasons that also came out of the war. Throughout eight years of bloody fighting, the Kuwaitis, like the Saudis, looked on -- as they are looking on now while others prepare to fight for them. They supported Iraq with money, which seemed only reasonable; but unlike the Saudis, they demanded full repayment, with interest. Expecting the debt to be forgiven, the Iraqis were stunned, and the dispute became increasingly acerbic until it exploded on Aug. 2 with the invasion.

It is no defense of that invasion to say that President Bush must now decide whether it is in America's interest to settle up with Iraq or make war -- and that is where the law of unintended consequences comes in. Do the president's advisers really believe, even if we win quickly and with minimal losses, that our Army would be able to pack up and come home?

It would take a monumental effort to put the Humpty-Dumpty of the Middle East back together, and the United States -- with its money and its men -- would be stuck with doing it.

Iran would be at the top of the agenda. It is naive to think that the revolution, though currently demoralized, has outgrown expansionism. Khomeini, before he died, made clear his belief that the cease-fire was temporary. If we now destroy Iraq, we would still have to re-create it as a military power -- unless we are prepared ourselves to remain for years on the Euphrates.

What makes far greater sense is for us to figure out what kind of order we can live with in the Middle East -- taking into account not just Kuwait but arms and oil prices, and maybe even the Israeli-Palestinian dispute. Then we ought to get on with negotiations, because even a victorious war would bring no end of surprises, unpredictable in nature but surely unpleasant.

Milton Viorst, a Washington writer, covers the Middle East for The New Yorker.