With All Mideast Armed, Crisis Sits Atop Powderkeg : Weapons: Israel has nuclear and chemical arms, Iraq has chemical and biological, others are also armed--and thresholds for action are unknowns.

The key players in this month’s Middle East crisis all have weapons of mass destruction: a blanket term for nuclear, chemical and biological arms that kill huge amounts of people with impersonal, indiscriminate bluntness. And so, a new study by two strategic analysts at Britain’s Bradford University warns that any war that develops “could have massive and unpredictable consequences.”

Particularly dangerous is the fact that the thresholds, or limits to an army’s tolerance, are unknown. Conventional warfare, using bullets and grenades, would be bad enough; but what would it take to bring on the mass destruction?

What would prompt Iraq’s Saddam Hussein to unleash chemical or biological weapons in the current confrontation? Where is the threshold at which Israel would feel it must use a nuclear bomb? Could any level of threat or actual violence justify use of tactical nuclear weapons--even a high-radiation, low-blast neutron bomb--by the U.S. forces now in the gulf?

These questions have been troubling Israeli policy-makers for years. They do not confirm publicly that they have a nuclear arsenal, but Western intelligence analysts believe Israel has more than 100 nuclear bombs of various sizes and types.

Iraq’s obvious willingness to use weapons of mass destruction--seen in the poison-gas attacks on Iranian soldiers and Iraqi Kurds suspected of disloyalty during the Iran-Iraq War--add an extra dimension to Hussein’s grab for glory this month. Israeli strategists fear that Hussein’s ultimate goal goes far beyond the oil wealth of captured Kuwait or Western-backed Saudi Arabia, extending all the way to the destruction of the Jewish State.

Israelis are concerned that Saddam might order his army to lob a chemical or biological shell toward Israel, without regard to a missile’s accuracy, simply to shake up the pot and start a wider war that might unite all Arabs.

In war games and joint analysis of options by Israeli and U.S. experts, they consider an Iraqi attack on Israel to be a worst-case scenario--but a possibility.

The Israelis have been tempted to launch a preemptive strike, especially when their intelligence agencies report Iraq is only five years away from developing a nuclear bomb. But they appear to accept that they cannot indefinitely enforce the so-called Begin Doctrine.

It was in June, 1981, that Prime Minister Menachem Begin sent the Israeli air force on its then-longest bombing raid: to destroy the nuclear reactor that France had supplied to Iraq. Begin’s nightmares of the Nazi Holocaust prompted him to declare the enemies of Israel and the Jewish people must never be allowed to obtain weapons of mass destruction.

Now, however, intelligence reports say the Iraqis have spread their secret military facilities around the country and “hardened” them underground to make them less vulnerable to air attack. In addition, Israelis say Hussein sounded serious in April, when he threatened to destroy half of Israel with chemical weapons if the “Zionists” dared to attack.

It was startling to hear Hussein confirm that he had these weapons, but Iraqi officials said they were merely trying to match Israel’s military superiority. Western analysts call chemical and biological arms “the poor man’s nuclear weapon.”

If Hussein and other Arabs continue to be convinced that Israel could destroy them, would that deter war? It was Israel, after all, that introduced nuclear fears into the Middle East. The world knows Israel has the bomb, despite lack of official confirmation--certainly since nuclear technician Mordecai Vanunu in 1986 gave a British newspaper photographs and a detailed account of the secret weapons factory under the Dimona atomic reactor in the Negev desert.

In the late 1950s, Israel purchased MD-660 ground-to-ground missiles form France, and--standard practice in Israel--manufactured home-grown versions. The public debut of one carried Israel’s first satellite, Ofek, into orbit on Sept. 19, 1988. The Israelis had a second, experimental Ofek in orbit from April to July this year.

Less than three weeks ago came a further, thinly veiled warning to Iraq, when Israel tested its anti-missile missile for the first time. The Arrow anti-ballistic system is largely funded by the U.S. Strategic Defense Initiative program.

In this current crisis, the Israeli public has been told that millions of gas masks are ready for distribution--but there is no need because Iraq does not have chemical warheads and any Iraqi warplane flying toward Israel would be shot down. To keep morale high, the army has said that Israel’s chemical warfare countermeasures are the best in the world.

The Israelis still believe in maintaining a technological edge over their enemies. They increasingly put their faith in deterrence, hoping that selective leaks about Israel’s “non-conventional” arsenal will be enough to deter the Iraqis from starting a war.

Reports from the CIA and Israel’s Mossad, however, emphasize Hussein is determined not to surrender to international pressure and still hopes to have his own nuclear arms with appropriate means of delivery.

Regardless of how the current crisis resolves itself, whether through diplomacy or battle, Israel feels it is facing a clock ticking against its interests. The Israeli people do not want Iraq to have nuclear weapons. No referendum has ever been taken, however, as to when or how Israel should use nuclear bombs in the name of self-defense.

The only threat the Israelis can make is the vague, but potent, one: “Iraq will not be the same Iraq” if Israel is attacked. Specifically, Defense Minister Moshe Arens has threatened massive attacks by the Israeli air force if Iraq sends troops westward into Jordan as an implicit move toward Israel.

Science Minister Yuval Neeman went so far as to confirm that Israel could respond to Iraq’s chemical-weapons threat by responding “with the same merchandise.” It was a rare mention of Israeli weapons capabilities--normally shrouded in official secrecy and military censorship.

For many years, successive Israeli governments tried to prevent local and foreign journalists from publishing stories about the development of non-conventional weapons--and even conventional ones--by Israeli scientists and defense contractors.

Discussion has lately become freer, although on the biggest taboo the government continues to stick to a well-worn slogan: “Israel will not be the first to introduce nuclear weapons into the Middle East.”

Yet, according to Western intelligence officials and civilian analysts in the United States and Europe, Israel is no more than a few years away from developing submarine-launched cruise missiles as a second-strike arsenal. These could retaliate even if Arab forces managed to hit Israel’s nuclear reactor, ground-to-ground missile sites and air force bases.

Israeli strategists still have not worked out exactly when such weapons would be used, although analysts believe Israel has an extensive range of nuclear arms including small, “battlefield” shells.

By the same token, it is impossible to say precisely where the U.S. nuclear threshold stands in this unique desert mission. If Iraq uses even one mustard-gas or nerve-gas shell against U.S. forces in Saudi Arabia, would America “nuke” Iraq in revenge? Or only to prevent the GI’s in the gulf from being overrun by a million Iraqi soldiers?

The strategy is not to have a stated strategy; to keep the adversary guessing. Unfortunately, there is guesswork on both sides. U. S. intelligence is armed with the best satellite photographs and radar-readings from AWACS reconnaissance planes, but still cannot read the mind of a dictator. Only Hussein holds the key to how bad the conflict may get.