ISTANBUL -- Here in Turkey, the matter of headgear is taken seriously. An edict in 1925 forbade the wearing of the fez, causing millions of Turkish men to don bowlers, which were seen as more Western and secular. In 1982, the government of Turkey banned the wearing of headscarves by women in university classrooms -- a symbolic statement that Turkey would not be taking the route of the Iranian revolution across the border, which mandated the veil. But colorful headscarves are common on the streets here, worn in piety and protest. And the resulting headscarf debate is the Turkish equivalent of the American abortion controversy -- heated, culturally defining, admitting no compromise.

Haberdashery as political philosophy is unfamiliar to Americans. But this sartorial piety points to a large historical fact. From the Enlightenment to the sociological theories of the 20th century, it was assumed that religion was in decline and would be increasingly privatized and marginalized. Instead, as Professor José Casanova points out in his landmark book "Public Religions in the Modern World," we have seen the global "deprivatization" of religion -- a reassertion of religious values in defining the common good, from the Islamic revolution in Iran to the Solidarity movement in Poland to the religious right in America. As these examples show, the attitude of public religion toward democracy and individual freedom varies greatly -- and matters greatly.

This "deprivatization" has caused particular strains in Turkey, the most resolutely secular of nations. Religion, according to the Turkish constitution, is supposed to have no political or legal influence of any kind -- an ACLU utopia. The Religious Affairs Directorate supervises the training of all imams and determines the themes for Friday sermons. It is difficult to argue with the outcome of this model: Turkey is a prospering democracy where radical Islam has little traction. At the same time, Turks live with restrictions that would drive religious Americans frantic with resentment -- imagine nuns in habits being banned from the U.S. Capitol.

A series of political parties have called for the Turkish state to be more tolerant of public religious expression -- and been serially disbanded by the secular establishment. The latest incarnation, known as the Justice and Development Party (AKP), holds a majority in parliament, elected the current prime minister and seeks control of the presidency. This last move has provoked a standoff with the military, which has a constitutional role in defending the secular state. Prime Minister Recep Tayyip Erdogan has called for parliamentary elections July 22 to demonstrate his party's strength. That support increasingly comes not from the rural religious but from Turkey's growing middle class -- educated, entrepreneurial, pious and resentful of the secular elite.

Secularists accuse the AKP of seeking a slow-motion Islamist revolution. Turkish writer Mustafa Akyol -- a young, pro-American moderate conservative with a tendency to quote philosopher Leo Strauss -- regards this as a serious overreaction: "The AK Party has traces of Islamism, but it is moving toward becoming a conservative, Muslim democratic party," more akin to the Christian Democratic parties of Europe. So far, the AKP has been pro-capitalism, pro-European Union and a defender of Islamic family values, instead of being an advocate of Islamic law.

Turkish secularism has sometimes been called a political model -- yet even with its undeniable achievements, it is hard to imagine the export of this model to highly religious nations elsewhere in the region. But if the AKP proves itself as a center-right religious party, genuinely committed to pluralism, that will be a reverberating example. A democratic transition in Egypt, for instance, is not likely to be achieved by Jeffersonians and secularists. It will require moderate Islamists who direct conservative religious sentiments into democratic channels. Some believe that a "moderate Islamist" is a mythical creature, because Islam itself is essentially theocratic. But Muslims in Indonesia and Bangladesh, Morocco and Turkey are attempting to show otherwise. And America has a stake in their success.

Both sides in Turkey could undermine these hopes by overreaching. If the secular establishment were to disband the AK Party before the election, it would be a setback to democracy. If the AK Party, after a successful election, were to insist on a divisive presidential choice, it would call its long-term motives into question. Leaders of the AK Party have a serious responsibility beyond the defense of headscarves: to show that "desecularization" in the Muslim world is consistent with pluralism and freedom.