When Aramco engineer Ali Boureslan put in for a transfer from Houston to Saudi Arabia, he figured it would be a good career move. "I know the language, I know the traditions, the culture, the religion," said the Lebanon-born Boureslan, who became a U.S. citizen in 1977. "I thought, 'I'll be an asset to the company.' I thought I was."

Instead, Boureslan says, he was harassed by a supervisor who taunted him about his Moslem religion and his Lebanese background and refused to give him time off for religious holidays. Eventually, Boureslan was fired in what the company says was part of a reduction in force and Boureslan asserts was the culmination of a campaign of discrimination.

If the same things had happened to Boureslan in Houston, the lawsuit that followed would be a run-of-the-mill employment discrimination claim. Instead, it has become a Supreme Court case, testing whether the federal employment discrimination law stretches beyond the country's borders and protects U.S. citizens working for American companies overseas.

Boureslan, backed by the Bush administration, argues that when Congress enacted Title VII -- the 1964 civil rights law that bars companies from discriminating on the basis of race, sex, religion or national origin -- it meant to cover such bias outside the United States.

Otherwise, they said, more than 2 million Americans living abroad could find themselves stripped of anti-discrimination protections.

"In our view, Title VII's protections do not stop at the border," Solicitor General Kenneth W. Starr told the court last week. While the law does not address the issue explicitly, he said, "the most natural and reasonable inference to draw is that U.S. citizens are protected."

Boureslan's brief presents an array of potential scenarios that could arise if they are not: A U.S. law firm that opens a Paris office could bar black lawyers from working there in order to cater to the prejudices of a racist French industrialist, or keep female lawyers at home because it thinks they are less capable of protecting themselves against terrorist attacks. A company president could sexually harass a female employee on a sales trip to London, or decide to send home black and Jewish sales representatives in the belief that the British are hopelessly racist and antisemitic.

Aramco, supported by an array of other multinational employers, contends there is no indication Congress meant the law to have a global reach, and that interpreting it that way would create conflict with foreign governments and a host of other problems for companies.

Aramco's lawyer, Paul L. Friedman, reminded the justices of their 1982 decision that foreign companies doing business here must comply with Title VII. "Shouldn't we be bound by their employment laws and their discrimination laws when we do business as their guests?" he asked.

"It really is the height of chauvinism or imperialism or whatever to just say this is the way we do it in the United States, therefore it must be right and we're imposing it on a foreign government," Friedman said in an interview, emphasizing that 55 countries have adopted their own anti-discrimination laws.

The issue of what is known as "extraterritorial jurisdiction" -- whether a U.S. law applies overseas -- has become especially important in an age when business is increasingly international in scope, and when a foreign assignment may be a critical step in career advancement.

The fact that it has come before the high court at a time when U.S. forces are fighting in the Persian Gulf also gives the case what some see as an ironic twist and what Friedman says makes the government's position "particularly disingenuous": while U.S. military authorities instruct soldiers in Saudi Arabia to dress modestly or curtail their religious practices out of respect for local customs, the U.S. government here is telling employers they may be hauled into court for taking the same "When in Rome, do as the Romans do" approach.

"It is quite appropriate for the U.S. government to impose such restrictions on its own civilian and military personnel in Saudi Arabia out of a concern for the religious and other practices and sensitivities of their foreign host," said a personnel managers' organization in a brief filed on Aramco's side. "It is inconsistent, however, for the same government" to prohibit U.S. companies to make the same kind of concessions.

Equal Employment Opportunity Commission lawyer Samuel Marcosson said the administration's orders to soldiers in Saudi Arabia represent a "simple matter of courtesy and practicalities in what amounts to an extremely unusual situation."

He said the EEOC, which enforces Title VII, would not hold employers liable if their discriminatory actions were compelled by foreign law. Saudi Arabia, for example, requires that men and women work separately from each other and prohibits "adolescents, juveniles and women" from working in designated "harmful" occupations or at night. "We're not saying that foreign companies should have to violate Saudi law in order to operate over there," Marcosson said.

Both sides agree that courts generally will not apply U.S. laws overseas unless Congress has made it clear it wants that result -- a rule first set down nearly a century ago by Justice Oliver Wendell Holmes.

They agree as well that the question is not whether Congress has the power to apply Title VII abroad -- it does -- but whether it did so clearly enough to overcome the general presumption against extraterritorial jurisdiction. (If the court rules the law does not apply abroad, Congress can make the change itself, as it did with the federal age discrimination law in 1984, after several appeals courts held the law did not cover workers overseas.)

The EEOC has some 50 cases involving allegations of discrimination overseas on hold while the Supreme Court decides the Boureslan case. A federal judge in Washington state ruled last June that two American women working for Boeing in Turkey could sue the company for sex discrimination for changing their payments from U.S. dollars to the less desirable Turkish lira on the ground that their marriage to Turkish men made them Turkish nationals under that country's law.

Refusing to apply Title VII overseas, the NAACP Legal Defense and Educational Fund argued in a brief, would create "a massive loophole" for companies that want to circumvent the law, permitting employers to "launder" discrimination simply by sending employees overseas.

Indeed, the EEOC's Marcosson said, American employees oversees may be even more in need of protection from discrimination than those here, precisely because U.S. companies may feel the need to adjust their operations to foreign stereotypes and values such as an unwillingness to deal with women.

Such discrimination by U.S. firms, he said, should be prohibited "for the same reason an employer in Birmingham or Montgomery in 1965 shouldn't have been able to say that I won't hire blacks for my restaurant because no white customer will be willing to be served by a black person. You can't allow the law to give way to those prejudices."

Those arguing against applying the law overseas say it would cause enormous problems for multinational corporations. For example, they note, nothing in the law expressly limits it to U.S. companies -- meaning that applying it overseas could cover foreign companies that employ U.S. citizens. In addition, they say, it could create collisions with foreign laws -- such as the Saudi restrictions on female employees -- that will put companies in an impossible situation.

Those on Aramco's side also say it would be unfair to hold companies liable for the acts of foreign employees -- such as Boureslan's British supervisor -- who may not be operating under the same moral code.

"The social mores of certain Latin American and European cultures may permit as perfectly acceptable words or conduct that may be offensive here in the United States and proscribed by the EEOC's rules on sexual harassment," the personnel group noted in its brief.

"People understand when they accept overseas assignment that the rules of the game are different," Friedman said. "The air you breathe may not be as clean. The water you drink may not be as pure. . . . The rules of the road on which you drive are different. And the laws of the workplace are different."