The Bush administration, after building a vast and often improbable network of allies through two weeks of adroit diplomacy, now faces the more daunting task of sustaining the coalition against Iraq -- perhaps for months -- in the face of centrifugal forces that could pull it apart.

Through persuasion, pleas and pressure, the administration has welded dozens of disparate national interests into a common crusade aimed at forcing Iraq out of Kuwait. This loose confederation unites East and West, rich and poor, traditional U.S. allies and erstwhile U.S. foes -- notably Syria and the Soviet Union.

Yet putting the coalition together may have been the easy part, administration and congressional officials agree.

"What's drawn the disparate parties together -- the Soviets, the Arabs, the Americans, the Europeans and the rest of the world community -- is the shared assessment that Iraq's invasion represents a threat to common security," Rep. Lee H. Hamilton (D-Ind.), chairman of the House Foreign Affairs subcommittee on Europe and the Middle East, said Friday. "A lot of things could happen that would threaten that consensus. You have to keep a lid on the outbreak of war. You've got to try to maintain the embargo without using a lot of firepower . . . . Time does not work for us here. Any sanction effort is subject to strains."

In simplest terms, most of the world has embraced a version of the U.S. government's argument that Iraqi President Saddam Hussein is a menacing outlaw who threatens to plunge civilization into "a new dark age" with his armed aggression and control of a large fraction of the world's oil supply. This reasoning has persuaded even petroleum exporters -- such as China, the Soviet Union and Egypt -- who, for now, believe their long-term interests would be damaged if soaring oil prices prostrate the industrialized democracies and Third World "have-nots."

But U.S. officials fear this unity is fragile. Will Moscow remain staunch, for example, if the 8,000 Soviet citizens now trapped in Iraq and Kuwait are permitted to leave? How stalwart would Egypt remain if Saddam launched a wave of terrorist attacks and intensified his appeal for fundamentalist Islamic unity? What impact would televised pictures of starving hostages have on European resolve?

A senior administration official said last week that his greatest concern is West European or Japanese wavering if rising oil prices and uncertain supplies lead to lines at the gas pumps or political turmoil. "Bush has to keep two sets of things going at once: international support and domestic {U.S.} support," the official added. "We will do everything in our power to hang tough."

Perhaps the greatest unknown is how the current political alliance will hold up if war erupts. U.S. officials worry that many, if not most, nations might scurry to neutral corners, leaving the United States with few bleeding allies to fight for the industrialized West's way of life. "Once one bullet is fired," an Egyptian diplomat said last week, "we will face the severity of the task before us."

Bush has worked hard to force dozens of nations to choose sides in the confrontation with Iraq and has been openly scornful of fence-straddlers. Any defection from the alliance against Iraq, U.S. officials acknowledge, could make it easier for others to peel away from the sanctions effort. Yet, in many countries, the national interests that argue for aggressively thwarting Saddam coexist with countervailing interests that suggest neutrality, if not overt sympathy for Iraq.

The most conspicuous case is Jordan. King Hussein has a long relationship with Bush; he needs Saudi help in paying a $9 billion foreign debt and he counted on $135 million in Kuwaiti aid this year. On the other hand, Jordan gets 95 percent of its oil from Iraq, which also is the chief market for Jordanian exports.

"We are asking them to flush their economy down the drain," a U.S. official said this week. Jordan is militarily vulnerable to Saddam's legions and many Jordanians embrace a kind of Arab populism that resents Saudi Arabia and Kuwait for suppressing oil prices, thus reducing the potential flow of remittances to their less fortunate Arab cousins.

Although the Jordanian quandary is unique, similar debates of pro and con are being waged in capitals around the world. "What it basically boils down to is the great powers defending their national interests," former assistant defense secretary Lawrence Korb said last week. "If Kuwait grew carrots, we wouldn't give a damn."

But the powers, great and otherwise, have many national interests. Some converge with those of the United States, others do not. Here is a look at some of the issues at play in several nations. The Soviet Union

Bush's first, and perhaps most important, diplomatic triumph was in eliciting a prompt Soviet denunciation of the invasion. Moscow has adopted a stern line against aggression and in favor of collective security through the United Nations. But it has other interests.

The Kremlin desperately needs Western investment in the moribund Soviet economy; commentators in Moscow have distinguished between such "tactical" advantages as an increase in oil prices and the strategic goal of integration into the world marketplace.

Yet, as the world's largest oil producer, the Soviet Union stands to profit handsomely from the current turmoil. Though production has declined somewhat in recent years, Moscow pumps 11.6 million barrels a day and exports 3.3 million barrels of that, according to Robert Ebel, vice president of Enserch Corp. (By contrast, Iraq and Kuwait combined pump about 4.5 million barrels, or 9 percent of world production). The $10-per-barrel increase in world prices since the invasion of Kuwait translates into more than a $30 million daily Soviet windfall.

Moreover, the Soviets have a long relationship with Iraq, including a three-decade history of selling arms to Baghdad. The Iraqi debt to Moscow has been estimated at anywhere from $5 billion to $20 billion. Some U.S. analysts suspect Kremlin conservatives are not entirely dismayed at the prospect of the United States and its NATO allies mired in a Middle East quagmire. Japan

In past crises, Tokyo has been cautious to the point of timidity in dealing with Arab countries. But with growing self-confidence, the Japanese people are looking to assert their influence in ways other than raw economic clout. Prime Minister Toshiki Kaifu stresses his close personal ties to Bush, a bond that strengthens the Japanese leader's political hand. Japan, a country with modest defenses of its own, has an obvious interest in the success of collective action to rebuff Iraq's aggression. Tokyo also has tried to protect itself by stashing a five-month reserve of petroleum in tunnels on the southern island of Kyushu.

On the other hand, all Japanese oil is imported and 70 percent comes from the Middle East. If the United States appears to be on the losing side in the gulf confrontation or if a gory war begins, Japanese enthusiasm for the embargo could wane. And if Saddam woos back some Arab support, Japanese discomfort could increase; Japan also badly needs Iranian oil and, most analysts in Tokyo agree, would be susceptible to Iranian pressure, should it occur. Turkey

The government of President Turgut Ozal found itself trapped between its Western allegiances and a longstanding policy of regional neutrality. Though Ankara has tried hard to avoid antagonizing Baghdad in the past, the two neighbors already were at odds over a Turkish plan to build a large hydroelectric project on the Euphrates River, whose waters the two countries share; that enmity has grown considerably since Turkey cut Iraqi oil pipelines to the Mediterranean Sea. A member of NATO, Turkey recognized that failure to heed the embargo would badly damage its ties with the West and perhaps permanently preclude ever becoming the 13th member of the European Community.

But Ankara officials estimate the sanctions against Iraq could cost Turkey $2.5 billion this year, including a $300 million fee from Iraq for servicing the pipelines. Turkey also gets 60 percent of its crude imports from Iraq. "The Turks are going to pay for this more than anybody," a House Armed Services Committee staff member said last week. "They're going to be screaming within a matter of weeks." Washington has promised military protection and compensation; the Turks will be waiting eagerly for both. China

The gulf crisis is "a heaven-sent opportunity for China to burnish its international credentials," a Western diplomat in Beijing said last week. "It's a chance for China to show that it is a good international citizen, something it needs very much" after the massacre in Tiananmen Square last year. Chinese economic ties with Iraq are minimal except for some arms sales and Beijing would like Washington to lift the Tiananmen-inspired sanctions and retain most-favored nation trade status. Beijing's most immediate concern is the impact the crisis could have on the Asian Games, which would include athletes from many gulf nations, set to begin in China on Sept. 22.

But China views its adherence to sanctions in terms of lining up with the world majority rather than adhering to U.S. wishes, according to Chinese officials. If other countries abandon the sanctions, China could also; or, if the United States initiates military action, China could distance itself from Washington and the West. Egypt

President Hosni Mubarak remained silent for 30 hours after the invasion, reportedly weighing the many pros and cons of his predicament before decrying the Iraqi aggression. A U.S. diplomat in Cairo cites the extensive economic and military relationship between Egypt and the United States as "long-distance stuff" that will keep Mubarak aligned with Bush. Egypt owes more than $50 billion in foreign debts, including $12 billion to the United States.

As an oil exporter, Egypt earns an extra $70 million to $100 million per year for each $1 per barrel increase in the world price. But foreign exchange income from remittances earned by hundreds of thousands of Egyptian workers in Kuwait and Iraq are expected to drop by $1 billion or more. A protracted crisis in the Middle East will hurt the $2 billion Egyptian tourism industry.

Less certain is the impact Saddam will have with his new "Voice of Arab Egypt" radio station that exhorts the Egyptian masses to topple Mubarak. And with 5,000 troops now deployed in Saudi Arabia, military officials in Cairo are recollecting nervously their unhappy experience in the Yemen civil war of the 1960s, when 80,000 Egyptian troops ended up fighting for years. But having cast his lot against Saddam, it is hard to see how Mubarak would back off, officials said. West Germany

Like the Japanese, many Germans appear ready to ease away from the "global abstention" imposed by postwar military restrictions and reclaim a wider international role. After initial hesitation, Chancellor Helmut Kohl has indicated he wants to help bolster the armada assembling to enforce sanctions against Iraq; Bonn wants Washington to understand, according to Kohl's advisers, that a reunited Germany will do its part in international peacekeeping efforts. West Germany receives less than 15 percent of its oil from the gulf and only two percent from Iraq and Kuwait.

Yet West German sources warn that time is a critical factor; European support for sanctions could ebb as higher oil prices begin to hurt economically. Even the robust German economy is at risk, largely because of the huge costs of reunification.

Bush administration officials say they are aware of this complex weave of concerns around the world. For now, the strategy is to urge international unity, plug any leaks detected in the embargo, continue the military buildup and squeeze Saddam as quickly and forcefully as possible.

"We're going to have to have steely nerves as this thing plays out," a senior Senate staff aide said Friday. "Saddam probably has four to six months of supplies and he's going to see who blinks first. That's the question: who blinks?"

Contributing to this report were staff writers Dan Balz in Kennebunkport, Maine; Marc Fisher in Bonn; William Claiborne in Cairo; T.R. Reid in Tokyo; Lena Sun in Beijing; Nora Boustany in Amman; special correspondent Michael Z. Wise in Vienna and staff researcher Lucy Shackelford in Washington.