Raise your right hand and swear to tell the truth ... on the Koran?

As Muslim-Christian relations are under the spotlight around the world,US judges sometimes face a vexing question: Can witnesses raise their right hand and swear to tell the truth ... on the Koran?

The recent refusal by a Guilford County, N.C., judge to allow a Muslim woman to swear upon Islam's holy text before testifying is, in part, a new First Amendment challenge. And here in the Tar Heel state, the idea of swearing on books other than the Bible has reinvigorated a debate on the relationship between faith and truth that goes back to the founding documents of both the Carolinas and the country.

Certainly, some Americans, citing the nation's Judeo-Christian roots, dislike the use of the Koran in the court system. But, according to law scholars, allowing a range of holy books in oaths of justice may not only lead to a greater feeling of inclusion among religious minorities but also encourage them to tell the truth.

"For a long time it was part of the public trust to swear on the Bible before testimony, but today you have to ask a question: Is it really essential?" asks Derek Davis, editor of The Journal of Church and State and a professor at Baylor University, a Baptist institution in Texas.

Already, witnesses in American courts do not have to take a religious oath and can instead simply testify on pain of perjury. It's up to judges to decide what passes for an oath.

Most have apparently given other oaths wide latitude. In a federal terrorism case in 1997 in Washington D.C., for instance, the judge allowed Muslim witnesses to swear to Allah. And the practice isn't new: Mochitura Hashimoto, the Japanese submarine commander who testified in the court martial of a US Navy captain in 1945, was allowed by a military tribunal to swear on his beliefs of Shinto, the ancient religion of Japan.

But to Guilford County Superior Judge W. Douglas Albright, a 1777 North Carolina law clearly says oaths are made upon the "Holy Scriptures" - which scholars agree is a clear reference to the Bible. The Administrative Office of the Courts has so far declined a request by Muslim groups to make a rule change that would force judges to allow other religious oaths.

Since Judge Albright's decision, there's been a growing number of requests by other religious groups to have their holy texts allowable under law.

"It's gotten way out there: They've got everything from the Book of Mormon to the Book of Wicca on the list," says Judge Albright. "Our position is that the statute governs not only the type of oath, but the manner and administration of the oath, and that it's now a legislative matter to straighten out."

Legal experts say that both the "establishment" and "free exercise" clauses of the Constitution appear to prohibit banning the Koran. Indeed, some see the Guilford County controversy as another case of a US official promoting one religion over another.

"This case is a cousin to the Ten Commandments case in Alabama, where a judge does something that's pretty obviously unconstitutional, with a goal of sending a message ... that he's for fundamental religious values," says New York University law professor Noah Feldman, author of "Divided by God."

Muslims say the judge may be tapping into a post-9/11 ferment, with unspoken inferences to terrorism. "This shows there's a lot of anti-Muslim sentiment, especially here in the United States," says Arsalan Iftikhar, legal director for the Council on American-Islamic Relations in Washington.

But the Carolinas have their own unique role in the history of oaths. British philosopher John Locke, who helped forge the Fundamental Constitutions in the Carolinas in the 1660s, believed that atheists could not hold office or testify. After all, Locke wondered, how could anyone believe what they said if they carried no fear of God?

Yet the power of oaths has waned enough to make perjury laws necessary. At the same time, the Koran can be a powerful motivator to stick to the facts.

"The only thing more compelling [to] ... South Asian Muslims is to literally swear upon your mother's head, and mothers aren't as convenient to drag around in court as a copy of the Koran," says Manish Vij, a New York blogger who has written about the case on the website Sepia Mutiny.

Still, others say Americans should not lose touch with the country's Bible-rooted foundations.

"We don't have a state-run religion in this country and it's an honor to worship here, but some traditions that we've had for 200 years need to stay," says Michele Combs, communications director at the Christian Coalition in Washington.