At Front, GIs Ponder Combat Scenarios : Military: The possibilities range from quick victory to a long slugfest that could bring high casualties.

As they wait anxiously for the order to start a massive ground assault, U.S. troops throughout the Persian Gulf region have plenty of time on their hands to ponder and prepare for the many remaining Iraqi threats facing them. Among these are mines, attack helicopters and heavy artillery fire, possibly laced with chemical weapons.

If the final diplomatic minuet between Moscow and Baghdad fails, allied troops may quickly find themselves in that hellish battle.

“The scenarios range from a quick, easy victory--which is what everybody hopes for--to a long, drawn-out slugfest, which is what everyone is concerned about,” said Maj. Pete Peterson, a staff officer with the 1st Marine Division.

A key will be the speed with which allied forces, especially the Marines and the Air Force, can destroy the well dug-in Iraqi artillery at the outset.

The Iraqis have an almost 5-to-1 edge in artillery pieces over the Americans, and some of those weapons have longer range and possibly greater accuracy than similar U.S. equipment, allied officials say. Thus, it will be up to U.S. attack planes to locate, and quickly destroy, Iraqi cannons before they can pin down advancing allied forces.

“We’ll be under artillery, big-time,” said Marine Pfc. Charles Helmik. “We know there are going to be casualties. We just hope it isn’t too bad.”

Added Lance Cpl. Thomas Martin: “You have to prepare yourself for the worst. Then it can only get better.”

“This is not a piece of cake,” Brig. Gen. Charles Krulak, a Marine commander, agreed. “They’ve got a lot of artillery.”

“The hard part is the artillery,” added Maj. Bob Weimann, executive officer of a mechanized battalion of the 2nd Marine Division that will lead the way through the Iraqi defenses. “But I’m confident we can do it.”

The combination of artillery and the land mines may pose the most difficult obstacles for allied forces. Even without mines or gas, artillery in conventional warfare accounts for as much as half of all casualties. But in the present conflict, the Iraqis are believed to have laid down minefields, up to a mile across, in such a way as to channel columns of allied troops into “killing zones” where Iraqi shells can crash down on them.

It will be up to the Army engineers to clear paths for allied tanks. Later, the same engineers will have to turn around and clear different paths for troops and vehicles returning to the rear with the wounded.

“These guys are well-trained,” Krulak said of his engineers. “We have rehearsed--I mean to tell you, we have rehearsed down to the gnat’s rear end what we have to do, both expected and unexpected. They know what they’ve got to do.”

As the engineers navigate their way through the web of mines, berms and trenches that may be filled with burning oil, their task could be further complicated by chemical attack.

Senior U.S. Central Command officials, including Gen. H. Norman Schwarzkopf, have said publicly that they expect the Iraqis to unleash their existing stockpiles of chemical weapons. “We feel very strongly, obviously, that he has that capability,” Marine Brig. Gen. Richard I. Neal told reporters in Riyadh on Wednesday evening.

At the makeshift but well-camouflaged 13th Evacuation Hospital in northern Saudi Arabia, members of the nuclear, biological and chemical team have been busily rehearsing the complicated procedures they will have to follow if chemical casualties begin arriving.

The unit is supposed to receive warning of any incoming contaminated patients. Such an alert most likely would come from an odd-looking, six-wheeled vehicle known as the “Fox Reconnaissance System.”

These German-made vehicles with Mercedes-Benz engines and transmissions are capable of roaming the battlefield at speeds up to 80 m.p.h. From inside each vehicle, a crew of four would sample the air and ground for a score or more of gases, from mustard gas to nuclear radiation. The vehicle is equipped with robot arms and protective gloves so that the crew would not be exposed to the elements.

Using a computerized mass spectrometer that contains the chemical makeup for more than 400 known poisons, the rolling lab should be able to analyze the samples within seconds and then sound the alarm.

“The most dangerous agent we’re worried about is mustard gas,” said Lt. Col. Virgil East, deputy commander for administration of the Army’s 12th Evacuation Hospital in northern Saudi Arabia. “It doesn’t present itself sometimes for hours or perhaps days after it is on the patients.”

A single patient, he said, can contaminate an entire hospital, threatening the hospital staff as well.

Among the toughest decisions facing these doctors and nurses will be when to send a patient to the ward designated “expectant”--meaning expected to die.

“These soldiers will die no matter what we do, and they are given painkillers and made comfortable,” said Lt. Col. James Startzell, deputy commander of the hospital’s clinical services. “If a person has 60% of his skin exposed to mustard gas, and he hasn’t gotten it (clothes) off in two minutes, he is probably not going to live,” he added. “It might take them a week or two to go, but they are not going to make it.”

Last, but not least, is the threat of Iraq’s remaining fleet of about 200 attack helicopters.

“They can pop up out of anywhere. They’re hard to track,” said Capt. Jenks Reid, commander of one of the Army’s 24th Division air defense batteries.

The key defense against Iraqi helicopters will be the Vulcan 20-millimeter cannon, which is capable of firing 3,000 high-explosive or self-destructive rounds per minute. Vulcan gunners here characterize their firepower as putting up “a wall of steel.”

The 24th Division’s air defense crews believe the Iraqi helicopters will not operate independently, as U.S. helicopters do. Rather, Iraq’s helicopters are more likely to work in conjunction with specific ground units, they said. In any case, 2nd Lt. Dan Brewster predicted: “They’re going to be coming out of the woodwork.”

Despite the array of deadly obstacles facing them, as the possible start of a ground war looms, nearly all GIs exuded confidence to a degree that defies skepticism.

“The question is: Are they going to fight, and, if so, how hard?” said Maj. Peterson of the 1st Marine Division, speaking of the Iraqis. “Will they see the stranglehold we put on them and surrender? Or will they stay and fight to the last man?”

This report was compiled from combat pool reports reviewed by U.S. military censors.