As legislators and sectarian politicians in Iraq argue over anew constitution, they have frequently cited the role of Islam -- andIslamic law -- as a major sticking point.

The debate comes at a time when Muslims around the world are dividedover exactly how to define and apply Islamic law, or Sharia, as it is knownin Arabic. The fundamental challenge, scholars say, is that thecenturies-old legal tradition of Sharia, particularly in the Sunni world,has not coherently reinvented itself for modern times.

In its broadest sense, Sharia is a system of laws based on the Quran andthe life of the Prophet Muhammad. Like other legal systems, it has beenelaborated on and debated by trained scholars over the years. The result?Competing schools of legal thought over a body of work that primarilyaddressed the concerns of Muslim life beginning in the seventh and eighthcenturies.

Across the Muslim world, Sharia plays out in different ways, depending onwhether the local government is secular, strictly Islamist or somewhere inbetween. It also depends on how local Muslim scholars interpret the law.

"The role of Islamic law today is greatly reduced, except in a handfulof countries like Saudi Arabia, Iran and the small Gulf states," said FrankVogel, director of the Islamic Legal Studies program at Harvard Law School.

Of the 44 majority-Muslim nations around the world, only 10 declarethemselves Islamic states, according to a March report by the U.S.Commission on International Religious Freedom. Those countries, such as Iranand Saudi Arabia, try to weave Sharia into most aspects of daily life. Other more moderate states, like Jordan, declare Islam the officialreligion but apply Sharia only in limited cases, often involving family law.

"They may impact women unfairly, but many core Muslim values -- about familystructure and sexual relations -- are caught up in family law, and it's hardfor the state to venture into that area and alter what is seen asfundamental," said Vogel.

Then there are places like Tunisia, where Islam is the state religionbut aspects of Sharia -- polygamy, for example -- have been outlawed. Stillmore countries, including Turkey, are officially secular and have downplayedtheir Muslim identity. Others with mixed populations, like Nigeria, allowSharia to be used only in predominantly Muslim areas.

Why isn't Sharia already the law of the land in Muslim majoritycountries?

One answer, said Joseph Lowry, an expert on early Islamic law at theUniversity of Pennsylvania, is that "colonialism radically disrupted thesystem of classical Islamic law."

As universities and other secular institutions arrived in the Muslimworld, religious higher learning was marginalized. But in areas wherecolonial forces were less pronounced -- mostly Shiite areas -- scholars werebetter able to maintain their legal traditions, Lowry said.

Some of that is changing. In places where Muslims have grown discontentunder Western-style secular governments -- Egypt is a good example --increasing numbers have called for a return to Islamic law. "They invokeIslamic law as a symbol of opposition," said Lowry. "That's understandable,but it makes it difficult to implement."

But like a pre-modern traveler arriving in the 21st century, Islamiclaws that flourished in the early centuries after the Prophet Muhammad'sdeath do not fit neatly into the complex puzzle of modern society. "Historically the interpretation of Islamic law was in the hands ofscholars, not government officials," explained John Voll, professor ofIslamic history at Georgetown University.

Politically active Muslims, or Islamists, who want state-implementedSharia have rushed to simplify complex medieval jurisprudence to meet thedemands of modern government.

The result, said Voll, is often what he called "bookshelf Sharia." "That's the assumption of the Islamist program: that you can pull a bookoff the shelf called `Sharia law' and find an answer to everything," hesaid.

In drafting their constitution, Iraqis have fallen back on along-established principle in Sharia law, said Vogel of Harvard Law: thatthe state can adopt any useful measure as long it does not directlycontradict the Quran and the traditions of Muhammad -- the two main sourcesof Islamic law.

That idea can been seen in Chapter One, Article Two, of theconstitutional draft released Monday (Aug. 22), which states that "no lawmay contradict Islamic standards," according to an initial translation bythe Associated Press.

Although the same article also states that no law may contradict either"democratic principles" or other "essential rights and freedoms" mentionedelsewhere in the constitution, Vogel said the minimalist test of notcrossing Islamic standards may prove problematic.

"Treating women as identical in every respect to men might be seen ascontradicting Islamic law," said Vogel. Sharia law has traditionallyaccorded men and women different responsibilities, and therefore differentrights.