Regional Outlook : When the Masks Come Off Will the Coalition Hold? : Before the peace, the U.S. force will have to overcome a tough foe--the Iraqi Republican Guard.

EASTERN SAUDI ARABIA —  In the vast sands of nothingness to the north, they lay in wait, stropping their steel and thirsting for the blood of young Americans. Just mention of Saddam Hussein’s Republican Guards sends a bolt of fear through the Persian Gulf.

Each big war has its monster. This war’s is Saddam Hussein. And each monster breathes his own kind of fire. Hussein’s fire is his Republican Guard, 10 or maybe 11 divisions strong.

Reportedly arrayed in ready reserve in a sweeping arc behind the Iraqi-occupied front lines in Kuwait and at garrisons further north, the Republican Guards bring to battle a storied and violent reputation, earned in the bloody eight-year war with the Iranians and embellished by word of mouth among the troops and families of the U.S.-led military coalition.

By now, much of the world has heard mention of this elite corps, Hussein’s finest. If Iraq has a chance of sapping the will of its foes, its hopes rest with these men and their determination in a grinding ground war, according to accounts that have spread dread and colored the news throughout the West.

Storm troops. Battle-hardened. Crack. Lethal. Shock troops. Disturbing descriptions like these lace anticipatory dispatches from the war zone.

And indeed there is reason to fear: The Republican Guards know the sting of battle, they have endured massive casualties and pushed on, they are desert fighters positioned to defend home ground and, as seen from the West, they are driven by an incomprehensible zealotry.

Anecdotal accounts of the performance of Republican Guards in the Iranian war are of growing interest here in Saudi Arabia. One second-hand report told of guards pushing through chest-deep saltwater canals, advancing nonstop for 10 hours and not eating for 20 hours to press an attack.

In truth, though, most unclassified analyses rate the Republican Guard as equal in training and motivation to American combat troops, but certainly no better.

And some authoritative dispatches poke some rather large holes in the mystique of the guards. A British defense correspondent reported that the ranks of the guards were “understood” to contain soldiers as young as 16 years old, presumably reflecting the manpower shortages in Iraq resulting from the war with Iran.

For its own curious purposes, war often, if not always, finds the match of heroic and demonic military units, their men mythically larger-than-life. In Vietnam, captured Communist soldiers told of their fear of U.S. Marines, having been told Marines had to kill their mothers before going to war. The Royal Scots Dragoons still live in the glory of their famous and daring charge on gray steeds against Napoleon at Wellington. Turks are feared throughout the world because of their reputation for skill and brutality with knives--never mind that the blade is rarely employed in 20th-Century combat.

According to Western military sources, the Iraqi Republican Guards--or Presidential Guards as they are sometimes called--are a self-contained army apart from Hussein’s regular armed forces.

They have a separate chain-of-command direct to the president, bypassing armed services generals. They are better paid, better trained, better equipped and more highly regarded at home.

While that is to their great advantage as an organization, Western generals, who command more egalitarian armies, believe this elitism could be to the disadvantage of Iraq’s overall capabilities--a source of internal competition and division at a time when that nation is under tremendous stress, its leadership presumably finding control difficult.

During the political bluster leading to the Jan. 16 attack on Iraq, U.S. officials offered grudging respect for only one element of Hussein’s military, the Republican Guards. But it was an oblique compliment. “Their morale is unusually high due to their traditionally receiving special privileges and higher priority for supplies and equipment,” an Army colonel said.

Originally, the guards all came from Hussein’s home village of Uja, not far from Tikrit. Authoritative press accounts put the core number of divisions at six, with up to five new divisions added more recently. The actual number of men in the guards is thought to be about 150,000, although some estimates say the force is now larger, perhaps 250,000 to 350,000 men.

In total, Iraq is believed to have about a million men under arms, backed by a militia of about 850,000.

Trained by Soviets and equipped with Soviet-made T-72 tanks and other desert-proven armor, the guards are usually in the vanguard of important Iraqi military strikes. They led the way into Kuwait in August. And then, as is Hussein’s style, they were pulled back to leave regular army troops to hold the ground. Similar tactics were used throughout the war with the Iranians, who used American-made equipment.

In addition to tank and artillery brigades, the guards maintain their own air power, including reconnaissance and airborne early-warning aircraft. They are said to have their own combat engineers, commandos, medical units and supply channels.

Mobility and endurance are their credos. Defense analysts--although not necessarily those privileged to know of the U.S. plan of battle--believe the current deployment of the Republican Guards is meant to thwart two obvious avenues for an allied ground offensive: an amphibious assault near Kuwait city by U.S. Marines, or a flanking movement by heavy divisions of the U.S. and British armies around the west end of Iraq’s dug-in defensive line just north of the Saudi border.

For that reason, the Republican Guards have been savagely bombarded by multinational forces almost from the beginning of the air war. Returning U.S. pilots flying light bombers described round-the-clock, relentless attacks on the guards using, among other things, 500-pound cluster bombs--the goal being not only to destroy men and machines but also to demoralize these troops who could be the key to the defense of Kuwait.

“We just launched 40-plus airplanes to bomb them where they are dug in and camouflaged,” said Col. Manfred Rietsch, commander of Marine Air Wing 11. He spoke during the opening hours of the war. “ . . . It’s bound to have a psychological impact. It’s been a constant, controlled bombing without letup.”

He expressed the conventional military belief that to kill, confuse and rattle the elite guards “would have a demoralizing effect” on the Iraqi regular army troops.

U.S. officials in the theater of war also have given sketchy confirmation that American B-52s, with their deadly and unbelievably disorienting “rolling thunder” carpet bombing, have been put into use against the guards.

By the close of the weekend, officials of the Kuwaiti government-in-exile said they had evidence from Kuwaitis who stayed behind in the country that Republican Guards were almost constantly on the move trying to escape the aerial onslaught.

During the opening phase of the war, air power of the U.S. coalition was widely praised for its deadly punch and pinpoint accuracy. A more severe test of air power’s control of the battlefield will come when, and if, the soldiers of the coalition armies test just how much the battle-hardened Republican Guard has been softened.

This article was prepared in part from pool press reports passed through military censors.