Athens, Greece - Earlier this year on an Arabic Web site, a Muslim woman scholar posted an open letter to the Islamic world. "Take off the veil, sister," began Elham Manea, a professor of Yemeni descent who now works in Switzerland.
Her opinion was not new — that head scarves and other coverings for women are not mandated by the Quran or Islamic tradition. But the essay's impassioned tone quickly grabbed attention. Supporters hailed it as a timely manifesto against Islam's conservative tide. Traditionalists scorned it as the ramblings of a Muslim blinded by the West.
Both sides could agree, however, that despite all its cultural twists, the question of the veil is a religious one, and one that's stubbornly hard to pin down — just what does Islam demand?
With no central Islamic theological authority — such as the Vatican for Roman Catholics — Muslims are left to interpret Quranic passages, sift through stories about the Prophet Muhammad, known as hadiths, and study competing religious edicts over the various coverings. They range from fashionable head scarves to the shroud-like burqa and the full-face veil called a niqab, which may only show a woman's eyes.
"It's become such a charged topic," said Manea, a researcher on politics and Islam at the University of Zurich. "I received hate mail and e-mails with very threatening tones. But, on the other side, messages supporting my views also were overwhelming."
In the West — particularly Europe — the veil has been drawn into hot-button debates such as immigrant integration and worries about radical Islam. In many Muslim countries, it can represent a potentially life-shaping decision for women in which the veil is increasingly seen as a political statement against perceived injustices to Islam.
"There are so many pressures now to decide whether the veil is right or wrong," said Tarafa Baghajati, a leader of the European Network Against Racism in Brussels, Belgium. "The problem is that it's an impossible task."
Credible cases have been built in several directions.
Those supporting the veil often cite a hadith from Sahih Bukhari, a ninth-century theologian, that urges women to "cover themselves" in public. The Quran, too, contains sections that tell women to seek modesty and "draw their cloaks close around them" (Surah 33, verse 59) and "draw their veils" over their chests and necklines except around their husbands and close relatives (24:31).
Some prominent Islamic voices, including Egyptian-born cleric Sheik Yusef el-Qaradawi, say some form of Islamic coverings is supported by Muslim law and customs. But most don't go beyond advocating some variation of head scarves and body-covering clothing.
Far fewer leaders — outside ultraconservative bastions such as Saudi Arabia and Afghanistan — believe Islam requires veiling a woman's face and hands, saying that both are exposed during prayer and that a woman's face should not be covered during the Hajj, or pilgrimage, to Mecca.
But many other Islamic scholars find flaws in any demands for the veil, which is often called by the Arabic term "hijab."
They believe the phrasing in the Islamic texts are too vague to make it a religious requirement and reflects the cultural norms of the seventh-century life of Muhammad and later centuries — in the same way that the Bible and Jewish sources offer guidance that is now widely considered a matter of personal choice, such as a passage in I Corinthians that says women should cover her head during prayer.
"The hijab these days goes beyond religion into politics, culture and social," said Ahmed Nazeer, American Institute of Islamic History and Culture in Concord, Calif. "These pressures are all coming down on Muslim women — to make a statement in favor of the one vision of Islam or another."
Last week, a Turkish court acquitted a 92-year-old archaeologist, Muazzez Ilmiye Cig, who was charged with insulting religious feelings for her book that claimed Islamic-style head scarves were first worn more than 5,000 years ago by priestesses initiating young men into sex.
Turkey offers a vivid display of the modern interplay of the politics and shifting religious sensibilities.
Turkey's strongly secular laws ban head scarves in schools and public offices. But growing ranks of Turkish women favor head scarves in daily life — a trend echoed in some Muslim immigrant groups in Europe and elsewhere.
"There is powerful symbolism associated with the veil in the West," said Dogu Ergil, a professor of social and religious trends at Ankara University in Turkey. "It feeds into the insecurities of our globalized world: the threats to the way we look, the way we live and the fears about the stranger in our midst who may be hostile to our way of life."
Tariq Ramadan, a leading scholar on European Islam, told a London conference last week the veil was part of a deepening "them versus us" attitude.
"So many people can't see anything beyond the head scarf," said Iyman Alzayed, who works with an Islamic education group based in Vienna, Austria, and often lectures about her decision to wear a scarf. "With all the other misunderstandings between Western societies and Muslims, it's as if nothing matters except a piece of cloth."
Even Iran's Islamic regime shows the complexity of the hijab.
The 1979 Islamic Revolution imposed strict dress codes that allowed either a head scarf and formless coat or the billowing black chador, which covers all but a woman's face. Since the late 1990s, however, young women have been continually pushing the limits with the so-called "bad hijab." Now, it's possible to get by with a body-hugging tunic and a scarf that can reveal more hair than it covers.
Iranian religious authorities have been tongue tied. They realize any edict re-enforcing stricter hijab would be likely countered by liberal clerics acknowledging the desires of the young.
Instead, the theocracy has tried a stab at vanity — backing a fashion show in July that displayed their concepts of chic-but-conservative coats, head scarves and chadors.