Washington — In 1982, a defecting Iranian pilot flew his F-4 jet directly over a key Saudi Arabian oil terminal before he was detected. While this plane wanted only to land in peace, the incident underscores the military vulnerability of the Persian Gulf's largest country. Oil-rich but armed forces-poor, Saudi Arabia would be gravely threatened by a concerted foreign attack, United States analysts say.
``The Saudis are no match, ultimately, for Iran,'' says Geoffrey Kemp, a former Reagan White House national-security official.
Ironically, the proposed US arms sale to Saudi Arabia, which has generated so much opposition in Washington, would add only marginal capability to Saudi forces, military analysts say.
The arms package is made up of three main elements: AIM air-to-air missiles, Harpoon air-to-sea missiles, and Stinger portable antiaircraft rockets. But yesterday, Secretary of State George P. Shultz told Republican senators that the Saudis have agreed to drop the request for the Stingers (200 launchers and 600 reload missiles).
Under pressure from lawmakers, who say the Stingers could too easily fall into terrorists' hands, the administration had already been considering dropping them from the arms package.
According to International Institute for Strategic Studies figures, the Saudis already own older versions of all the weapons in the sales package. Saudi air defenses include 800 Stingers, for instance.
Congress has already voted to stop the sale. President Reagan will undoubtedly veto this blockage, but he has been delaying the move while trying to build support for his position on Capitol Hill. As of this writing, the Reagan veto was expected to come sometime today.
The proposed arms buy, which would be the third largest Saudi military purchase from the US in the last eight years, is only a small part of the Saudis' crash effort to buy a measure of national security through high technology.
A nation the size of the entire US east of the Mississippi, but with a native population only equal to that of the Philadelphia metropolitan area, Saudi Arabia sits smack in the middle of the most tumultuous region in the world.
To the far northeast, the Afghan war rages, making the Saudis nervous about Soviet designs on the Arabian Sea. To the southwest, its Yemeni neighbors have on occasion proved quarrelsome.
Any intra-Arab conflict -- between Egypt and Syria, for instance -- would find the Arabian peninsula in the middle. Perhaps most important, the overthrow of the Shah has turned Iran from a loyal shield of Saudi Arabia to a threat.
Oil has enabled the Saudis to throw wealth at their security problems. In 1983, the latest year for which full figures are available, the Saudis had the sixth-largest defense budget in the world -- about $22 billion.
But one of the most striking things about the large Saudi defense expenditures of recent years is ``the relatively small military establishment that they have generated,'' writes Nadav Safran, a Middle East expert at Harvard.
The regular Saudi Army is about 52,000 men-strong, smaller than that of Sudan. Nearby Syria (which, admittedly, is rapidly becoming an armed camp) has a 402,000-man Army.
The Saudis do have an additional 10,000-man National Guard, but its main function is internal security. It was the National Guard that was sent in to recapture the Mecca Grand Mosque in 1979, after it was occupied by fundamentalist insurgents. Reportedly, the guard performed poorly, taking twice as many casualties as the rebels.
Much Saudi money has been lavished on the country's Air Force, which has among the best weapons in the region. Its 205 combat aircraft (about half as many as Syria's Air Force) include three squadrons of F-15 interceptors, the top US plane, that were purchased in 1978.
It makes sense for the Saudis to focus their defense resources on air forces, US analysts say. It is the one branch of the service they can fully man, as air power is machine-intensive, and there are always young princes who want to be pilots. And air power is geared to fight the most immediate outside threat to the kingdom: raids on Saudi economic targets.
In 1984, for instance, an intruding Iranian jet was shot down by Saudi jets. Last month, missile-firing Iranian helicopters reportedly damaged a Saudi oil tanker.
``It's the most logical thing in the world for the Saudis to want sophisticated air defenses,'' notes Mr. Kemp.
Toward that end, the Saudis in 1981 bought five large AWACS radar planes from the US. The Pentagon now is getting ready to deliver the planes, and US opponents of this sale say they are gearing up to stop it, though the money has already changed hands.
Opponents of the AWACS transfer, such as Rep. Mel Levine (D) of California, say the Saudis have done little to advance the Mideast peace process and that the radar planes could be turned against Israel.
The Saudi Air Force already includes four smaller E-2 radar planes, such as the US Navy used skillfully against Libya. But their coverage is limited and the Arabian peninsula is vast.
In 1982, according to Harvard's Nadav Safran, another defecting Iranian plane -- this one a Boeing 707 -- flew across the entire mass of Saudi Arabia and landed in Egypt without being spotted.
Meanwhile, fundamentalist Iran is steadily regaining the military strength it had under the Shah, though that strength is for now all directed against Iraq.
The Iranian capture in February of Faw, an Iraqi port town, demonstrates that military professionalism is on the rise in Iran, says Ford Foundation analyst Gary Sick. The Faw assault was not a suicide attack of ill-trained militia, but a slick operation done under cover of a rainstorm, according to Mr. Sick.
Iran is inexorably gaining ground in its violent war with its neighbor. And it is being more bellicose in its threats, both verbal and armed, to shipping of all nations in the Persian Gulf.
``The fact is that Iran is the superpower of the region in terms of population and geographical position. And it is now exerting itself in the way that everyone has feared,'' says Sick.