THREATS AND RESPONSES: ALLIES; Jordan's King, in Gamble, Lends Hand to the U.S.

At his palace in the hills above this capital, King Abdullah II has been studying military maps of Baghdad.

As a former Jordanian Special Forces commander, the 41-year-old king has been anticipating an American attack on Iraq by calculating the hard choices facing Saddam Hussein. In addition to confronting besieging American troops, Jordanian officers believe, Mr. Hussein may face domestic uprisings -- most likely among the two million Shiite Muslims in Saddam City, a Baghdad district that is a suppressed cauldron of opposition to Mr. Hussein and his Sunni Muslim elite.

Among Arab leaders, few other than Saddam Hussein have a deeper interest in the outcome of an Iraq war than Abdullah does. Sixty percent of Jordan's five million people are Palestinians, many of them refugees bitter toward the United States for its support of Israel. Jordan also depends on a thriving trade with Iraq, its eastern neighbor, including cheap oil at savings of nearly $500 million a year, about equal to American aid to Jordan.

About 400,000 Iraqis are in Jordan. Most are fugitives from Mr. Hussein's terror, but some are secret police agents who, Jordanian intelligence officials say, may foment trouble. Jordan's eastern border with Iraq is open desert, allowing Iraqis virtually unhindered passage. A tide of Iraqi refugees flooding into Jordan to escape a war would be another major headache.

Yet Abdullah, the affable product of American schooling, is engaged in a big gamble.

In the face of overwhelming opposition to a war among his own people, the king has quietly assented to stationing American and British Special Forces in Jordan's eastern desert. Some units, Western diplomats say, are already operating deep inside Iraq, scouting targets. In addition, Abdullah has welcomed hundreds of American troops staffing three Patriot missile batteries that will seek to shoot down any Iraqi missiles launched against Jordan -- or, more likely, Israel.

He has also agreed to allow coalition aircraft to fly over Jordan to support the war effort, although Jordanian officials say no combat missions will be allowed. ''There will be no offensive missions flown from the west,'' one official said.

Although the cooperation has been masked, it is an open secret in the streets of Amman and in the teeming Palestinian refugee camps where anti-American feelings run high. Travelers on the 250-mile route from Amman to Ruweished, near Iraq, have reported sightings of uniformed American soldiers traveling the highway in unmarked vehicles, and others have reported heavy American equipment being unloaded at Aqaba, Jordan's Red Sea port.

Groups of trim, hardened, close-cropped Americans in civilian clothing checking into Amman's hotels on furlough are a common sight. Some are on military duty, others veterans working for private companies under Pentagon contracts. Asked what they have been doing in the desert, they offer wry smiles. ''Let's just say that Saddam Hussein is in for a few surprises,'' said one.

Jordanian officials say that Abdullah, told by President Bush at the White House last summer that he would not be dissuaded from military action to topple Mr. Hussein, chose to limit Jordan's losses. ''The king asked the president, 'Can I change your mind?' and the president told him bluntly, 'No,' '' one Jordanian official said. ''From that point on, we began preparing for war, and trying to minimize the political and economic costs.''

In a poll conducted in January by the Center for Strategic Studies at the University of Jordan, 98 percent of the respondents foresaw ''adverse repercussions'' for Jordan from a war; 88 percent opposed any support for American forces. Jordanian commanders are preparing for unrest if a war comes, with orders to crack down hard if protests turn violent.

For months, the American-educated technocrats Abdullah favors for his cabinet have been seeking to cushion Jordan against the economic fallout from a war. Aided by beneficial trade deals with Israel and the United States, currency reserves have risen to more than $3 billion, a record, and oil reserves have been built up. Saudi Arabia, prodded by the United States, has agreed to make up for any cutoff of Iraqi oil if war comes.

Jordanian officials say that Abdullah has shown a pragmatism that many contrast with the attitude of his father, King Hussein, who leaned toward Saddam Hussein before the gulf war in 1991. American aid to Jordan was suspended, and King Hussein was personally shunned, at least until he supported new Israeli-Palestinian peace efforts after the Oslo accords of 1992.

Jordanian officials say that Abdullah thinks his stand will be vindicated if a war goes according to American estimates. After talks with Gen. Tommy R. Franks, America's war commander, the officials believe Iraqi forces could be defeated in as little as a week, with American and British troops greeted by Iraqis as liberators. ''Who then, in the Arab world, will be more Catholic than the pope -- or more royalist than the king?'' one official said.

For Abdullah, who took the throne four years ago after King Hussein's death from cancer, the personal ironies run deep. Two weeks before his death, King Hussein abruptly switched the succession from his brother, Prince Hassan, to Abdullah, his oldest son. To Jordanians, King Hussein is an icon, a survivor of repeated turmoil during his 46-year reign, who guided Jordan from postcolonial fragility to a model in the Arab world for tolerance and adaptability.

But his father's handling of the 1990 crisis over Iraq has been a caution to King Abdullah. After Iraq invaded Kuwait, King Hussein described it as Iraq's reaction to Kuwaiti provocations over disputed oil fields. He urged the United States to leave the issue to Arab mediation, led by himself. He described Mr. Hussein as ''a friend and a new phenomenon in Arab politics.''

As war loomed in 1990, King Hussein eased the strain by roaring through his palace grounds on a BMW motorcycle, and he complained of sleepless nights. Abdullah, though, strikes visitors as calm. He tells guests with a smile that he reserves his motorcycle outings to breaks at a royal villa at Aqaba. His 32-year-old wife, Queen Rania, daughter of a Palestinian doctor driven from Kuwait after the Iraqi occupation, places her arm on the king's and says: ''My husband is a practical man. He gives us confidence.''

Nor is there much inclination, these days, to draw veils over the realities of Saddam Hussein's rule. Palace officials tell grim stories, dating from King Hussein's time, of fishing outings with Saddam Hussein and his sons, Uday and Qusay, that featured hand grenades instead of rods. ''They're thugs,'' a palace aide said.

Abdullah's approach has won support from many in Jordan's ruling elite, who say he has understood an opinion shift here. In 1990, Saddam Hussein was widely popular for his hostility to Israel and the United States. But while the Israeli-Palestinian confrontation stirs stronger feelings than ever, Mr. Hussein's appeal has dwindled, partly because satellite television now brings many Jordanians tales of his violent repression in Iraq.

In Palestinian refugee camps like Baqaa, outside Amman, Mr. Hussein's name still brings murmurs of approval, but many Jordanians grimace at his name.

Consequently, Abdullah's allies contend, a quick war to overthrow Mr. Hussein is unlikely to cause a major popular upheaval.

''If it's quick and surgical -- if Saddam is removed in seven days --nothing will happen; we'll be able to manage,'' said George Hawatmeh, editor of Jordan's principal Arab-language newspaper, Al Rai, published by a government-owned trust. ''But if it drags on for two months, four months, or, God help us, six months, there'll be a snowball effect, in Jordan and across the Arab world. How will anybody contain that?''

Still, many Jordanians, including some with links to the palace, say Abdullah may be veering too close to the United States for his own good. Some critics say privately that the king, as the son of an English colonel's daughter, Princess Muna, has the practicality of his English blood, but the liabilities, too, of not being fully attuned to Arab sensibilities.

The critics cite Abdullah's years at boarding schools in Massachusetts, and his early military training in Britain. In 1983, he spent six months training with the American military at Fort Knox. These experiences left him with an easy familiarity with American popular culture, critics say, but a shallower sense of Arab culture.

In the common nostalgia, King Hussein never lost touch with popular opinion, and he balanced Arab political imperatives with pro-Western instincts. Abdullah, an impatient modernizer, the critics say, alienated important constituencies even before war loomed, including moderate Islamists and some tribal leaders.

Abdullah came to the throne with calls for a move toward fuller democracy, but the rising conflict between Israelis and Palestinians, and America's response to the Sept. 11 attacks, roused popular feelings that prompted him to reverse course. Parliament was suspended and elections postponed. Permits were required for protests, and few were granted. Tighter press controls were imposed. More than 120 new laws have been passed by royal decree.

Unions and professional associations, a powerful pro-Islamist force under King Hussein, were barred from political activities. This week they struck back in a joint statement warning Jordanians that any cooperation with American troops here would betray Islam.

Last Oct. 28, an American diplomat, Laurence Foley, was shot to death outside his Amman home by men American and Jordanian investigators have linked to Al Qaeda. A few days later, the government cracked down on Islamic militants in Maan, a tribal stronghold 140 miles south of Amman, bringing violence that killed six people.

Maan still feels like an armed camp. Armored military vehicles idle at street corners and angry residents offer tours of the pock-holed masonry. Saddam Hussein, in these streets, is a hero.

Suleiman Muhammad al-Khatab, a 54-year-old Bedouin leader, said anything that undermined Mr. Hussein would backfire. ''If King Abdullah supports a war, we will oppose him to the utmost,'' he said.

''To us, Saddam Hussein is a real man, a real leader and symbol of the Arab nation.''