A jittery Saudi Arabia has made its most assertive move yet to stem escalation of the Iran-Iraq war. But despite the Saudis' announced downing of a presumably Iranian warplane near their coast Tuesday, the war seems increasingly to have boiled down to an intractable contest between Iran and Iraq for wider political dominance of the Middle East.
Iraq seems in better shape on this score, although still not visibly near anything resembling outright victory.
And indeed, one historical focus of regional rivalry, the Arab-Israeli conflict, may be circumscribed for some time by this battle for supremacy.
Militarily, amid fresh outbursts of ground fighting and a reported Iraqi air strike on an Iranian frontier town Tuesday, the stakes in the Gulf war seem to be rising irresistibly. The Iranians promptly vowed to bombard Iraqi towns in retaliation.
Iran is believed to be gearing up for a major ground offensive, aimed at foiling Iraq's publicly proclaimed bid for an early peace. Iraq has threatened to counter any such thrust by escalating the recent ''tanker war'' in the Gulf and ''destroying'' Iran's main Gulf oil-shipping outlet at Kharg Island.
The Saudi shootdown Tuesday, the first such move since the tanker war began, was seen as signaling a new determination in Riyadh to halt the war's escalation.
But it would be premature to assume the Saudis will succeed in that aim, much less in bringing the Gulf war to a halt. For the ultimate stakes in the 31/2 -year-old conflict are political. And this, in the eyes of many Mideast analysts , implies a fight to the finish that would-be ''mediators'' may be hard pressed to curtail.
Iraq's President Saddam Hussein seeks leadership of an Arab world in which Egypt's traditional role has been trimmed by peace with Israel. In the bargain, he would like to humble his bitter rival, Syrian President Hafez Assad.
Iran's Ayatollah Ruhollah Khomeini seeks regional sway for his brand of militant Shiite Islam - if possible, atop the ruins of regimes in Iraq and more than a few of its Arab oil neighbors.
Intensifying the conflict are various lesser rivalries. There is the personal battle between Saddam, as he is known in Iraq, and the Ayatollah. There is the millenniums-old tug of war between Persian and Arab in the Mideast. But at issue , above all, is the future power structure of a region that, the current world oil glut aside, remains of strategic world importance in the longer run.
For many months, until recently, that question had been muddied by an Iran-Iraq war of attrition that focused most attention on the internal economic and political staying power of each combatant.
Iraq was getting the worst of that bargain. With only a small outlet on the Gulf, Iraq had seen its own crucial oil-export earnings trimmed far more severely than were Iran's. And Syria shut down the pipeline through which Iraq had funneled much of its oil to the Mediterranean.
But by prompting the tanker war in the Gulf, Iraq has done much to even the scales. Iran, for the first time, is feeling the oil-export pinch. And in its counterattacks on tankers outside the war zone, Iran has acted as a vehicle for Iraqi pressure on the outside world to deliver a war settlement on Baghdad's terms.
One major lesson of the war is clear: Iraq and Iran have each miscalculated the potential for the internal political disintegration of its rival.
Saddam figured that ethnic Arabs in Iranian border areas would welcome him as a conquering savior. No such luck.
And the Ayatollah figured Iraq's Shiite Muslims - a majority that had intermittently erupted in violent opposition to the regime - would fight, if at all, on the side of Iran. Again, no such luck.
Still, there is no convincing sign as yet that either Saddam or the Ayatollah has abandoned the search for victory in the conflict, Arab political analysts argue.
For the Ayatollah, the aim remains to topple Saddam by attrition even as periodic car-bomb and other strikes elsewhere in the Arab world encourage uneasiness among the collection of monarchs and strong men who have dominated Arab politics for the past decade.
For Saddam - who, Arab analysts note, has quietly reformed his military on the criterion of professional competence rather than mere political docility - the hope is to insert himself at the head of a revised, post-Camp David Arab power structure.
By this reckoning, the Egyptians, the Saudis, and others would then combine to facilitate a later contest for leadership with neighboring Syria.
If there is a prospect for short-circuiting the Gulf conflict, Arab analysts suggest, it lies in the possibility that currently pro-Iraqi Arabs like the Saudis and Egyptians will begin pressing much harder for Saddam to stop while he is, if not ahead, at least in much better shape than seemed possible a few months ago.
Since the Saudis have been key in funding the Iraqi war effort, such pressure would seem practicable. Yet at least at time of writing, Iraq's ability to calibrate the widening tanker war is giving Saddam considerable leverage of his own on the Saudis and other Arab oil allies.
Similarly, Egyptian military backing for Iraq offers Cairo a lever on Saddam. Using it would be in line with Egypt's hopes both to end the war and to reassert its own leadership role in the Arab world.