FOR months, Americans have worried lest their nation's military involvement in the Gulf lead them into a quagmire. No doubt the US strike on offshore oil rigs used as bases by Iran's Revolutionary Guards was ``measured,'' just as Defense Secretary Caspar Weinberger has stated.
But two changes in the rules of engagement that previously governed US military responses in the Gulf were involved.
First, while United States forces had before been protecting reflagged tankers in international waters, the United States now responded to an attack in Kuwaiti territorial waters, where US warships had thus far been refused entry. The attack was chiefly a problem of Kuwait, not of the US.
Kuwait is understandably reluctant to kick dust in Iran's face. But it could have asked Iraq, rather than the US, for help. After all, the Silkworms fired in this case were deployed on Iraq's Faw Peninsula, captured by Iran last year. The missiles lie closer to Iraqi helicopter gunships than to US military forces.
Instead, the Kuwaitis cast the issue as a question of US credibility. Most likely they, like the Iraqis, have concluded that their interests are served by maneuvering the US into a wider conflict that might injure Iran more than Iraq alone has been able to do. By retaliating, the US did nothing to resist this ploy.
Second, while the US had previously confined its military responses to direct threats as they occurred, it left Iran's Silkworms untouched. Instead, an oil platform was pummeled which posed no immediate threat to US forces or tankers. Apparently when the immediate threat is too hard to hit, US forces may retaliate elsewhere.
These changes in the original rules of engagement are marginal. Yet in making them the US has gently tiptoed over a fine line between a strategy of pure point defense and one of proportional response; in the latter the US defines what is a transgression and what is a ``suitable'' response. The former has inherent limits; the latter does not. Given Iran's demonstrated tolerance for pain, proportional response risks endless escalation.
Perhaps this is what Iran's leaders expect. They have said repeatedly that they know very well the kind of damage US forces can inflict. They worry that this US President in particular would like nothing better than to visit evil on Iran, perhaps even gut the Islamic revolution.
That the US is now allowing itself to be maneuvered into a wider military involvement only confirms this view. So does Mr. Weinberger's recent public statement that the world needs a new government in Tehran. No American need worry that Iran is not ``getting the message.''
The question is whether this is a helpful message to send. Iran now faces a degree of global and regional isolation it has not had since 1980, when it held US diplomats hostage. International pressure, far more than the threat of US military retaliation, has helped bring Iran close to a reasonable negotiating position at the United Nations. Iran no longer insists on the fall of Iraqi President Saddam Hussein as a condition for negotiations. But it refuses to retreat to internationally recognized borders until after a UN-commissioned tribunal reaches the ``obvious'' judgment that Iraq started the war.
The reflagging operation helped forge the international consensus that now pressures Iran. The Europeans, for example, probably would not have sent their navies to the Gulf, had a larger US force not already been there. But the only other useful purpose now served by protecting reflagged tankers is to demonstrate that the US will ``stay the course''; the US can do that without changing the rules of engagement.
Indeed, expanding the US military mission in the Gulf is likely to be counterproductive. US pressure is more likely to drive Iran toward the Soviet Union than toward collapse or capitulation. Some of Iran's leaders may fear major US military action. But the vision of fighting the ``Great Satan'' still evokes strong passion in others. Like taking US hostages in 1979, such a conflict can be used to silence more-pragmatic leaders who might be looking for a way out of the war with Iraq. An expanding military engagement thus is likely to undermine the UN cease-fire effort - the only way out of the current imbroglio.
Rather than make unilateral military moves, the US should seek to submerge its military operations in a united international front. The US currently opposes efforts to bring the multinational military force now in the Gulf under UN auspices. Yet this may be the best way of heading off a US-Iranian confrontation.
If the UN cease-fire effort should collapse, the US will need all the allied support it can get to deal with the nastiness that is sure to follow. But that's all the more reason to move back into the consensus of the UN Security Council, seeking to cement in place the multinational support the US now enjoys.
By itself, last week's attack does not prevent the US from pursuing these goals; yet it does suggest that the administration may be overestimating the role played by military threats and underestimating the effects of direct US pressure on Iranian politics. If that's the real message in the retaliation, we may be in for a long, lonely, and very dangerous stay in the Gulf.
Thomas L. McNaugher, a research associate at the Brookings Institution, is the author of ``Arms and Oil: US Military Strategy and the Persian Gulf.''