Chemical Attack Would Escalate Allied Retaliation : Tactics: Iraqi use of poison gas could trigger a march on Baghdad to hunt down Hussein, officials warn.

U.S. and allied officials warned Wednesday that any significant Iraqi use of chemical weapons against coalition troops would lead to a major escalation of the war and could trigger a contingency plan for a march on Baghdad to hunt down Saddam Hussein.

Already, allied forces are attempting to discourage front-line Iraqi artillery crews from obeying future orders to fire chemical shells, notifying them in leaflets that they would be pursued individually after the war--much as some Nazi death camp guards have been brought to justice decades after World War II ended.

Major use of chemical weapons, a violation of international law, would cross a “red line beyond which all previous bets are off,” said a senior Bush Administration official involved in the final preparations for a ground war.

“It’s a red line that would compel the coalition to change its own objectives--adopting, for instance, a march on Baghdad to find Saddam and eliminate his regime,” he said of the Iraqi president.

A senior Arab official confirmed Wednesday that the allies have prepared specific plans for retaliation if Iraq wages chemical war.

“We’ll use the unimaginable, short of nuclear weapons,” he said. That includes the option of going to Baghdad “to find Saddam and kill him,” he added.

The U.S. official did not go that far, saying only that once detained by allied troops, the Iraqi leader could be put on trial for war crimes, just as Nazi leaders were at Nuremberg, Germany, after World War II.

The official warnings came as the certainty of a ground war mounted in Washington--and with it, optimism that allied ground forces could prevail easily against battered Iraqi troops. But the officials’ renewed focus on chemical weapons reflected continuing concern about one of the most potent weapons left in the hands of Iraqi troops.

Although senior Administration officials have said publicly that Iraqi use of chemical weapons would have “massive and grave consequences,” none have suggested before that their use could trigger such a significant expansion of the allies’ war goals.

In a ground war, American troops would be expected to march into Iraq in an effort to envelop Iraqi troop positions. But officials agree that such a strategy alone would not require U.S. ground forces to approach Baghdad, the capital.

During the U.S. invasion of Panama, deposed leader Manuel A. Noriega was ultimately apprehended by U.S. troops, but only after a frustrating weeks-long search. Despite that experience, several political officials said that the Bush Administration might order a manhunt for Hussein under special circumstances.

“If he does not use chemical weapons, I think people will squeeze him out of Kuwait and lock him into Iraq,” said a senior official of a key Arab country. But if Iraq uses chemical attacks to blunt an allied ground war, the official said, the allied forces could hunt down and kill Hussein.

U.S. commanders have said in recent days that they are certain that Iraq would use deadly nerve agents--including rockets filled with cyanide gas--against American soldiers. As a result, the first U.S. troops entering Iraq and Kuwait would be fighting in gas masks and bulky chemical protective suits, cutting down their effectiveness and slowing the pace of battle.

“This war will be chemical probably from the very first hour,” said a military intelligence officer in Saudi Arabia. “Personally, I think it’s another miscalculation” on the part of Hussein, the officer added. “He seems to think it’s going to sap our will to fight, but I think it’s just going to (irritate) American troops more.”

The officials’ comments also marked the most explicit indication to date of how the U.S.-led coalition would react to Iraq’s use of deadly nerve agents. Among the principal options, officials said, was a significant expansion of the geographic boundaries of the ground war.

Some officials have said that Hussein already has given troops dug into positions in southern Kuwait the authority to use chemical weapons against any allied assault. As a result, a sophisticated allied effort has tried to communicate warnings not just to the Iraqi leader but also to the troops who would carry out such orders in the field.

Between furious aerial assaults, Iraqi positions are being bombarded by thousands of leaflets warning troops that they might face trial for war crimes if they use chemical weapons, a senior Arab official said.

He said the leaflets are intended to encourage the troops to disregard orders they may receive from their superiors, all the way up the Iraqi chain of command to Baghdad and Hussein, to unleash the feared poison-gas weaponry.

The same message is being broadcast to Iraqi front-line troops by five separate radio stations. The radio broadcasts have been set up by U.S. forces since the war began, using Saudi financing and Iraqi emigre broadcasters, the Arab official said.

The fact that the use of the weapons was ordered by higher-ups would not be considered an acceptable excuse, the official said.

In effect, he said, the pamphlets are telling the troops and their officers: “We’ll grab you and try you for it. We’ll find you, try you, and kill you.”

The U.S.-led coalition has also used the airdrop of pamphlets to encourage Iraqi soldiers to lay down their arms and defect. The leaflets, printed in Arabic, have provided a guide to the proper method of surrender and have been waved overhead by soldiers seeking protection behind allied lines.