ISTANBUL, Turkey – For most Americans, the most important day this month is December 25. For Turks, it’s December 17. Today, the European Union will announce whether it will open full membership negotiations with Turkey. In contrast to the ambivalence that surrounds the E.U. in most of its member states, Turks seem to be, almost without exception, enthusiastic about falling under the sway of a Brussels bureaucracy. E.U. membership is widely expected to deliver an economic windfall in the form of greater trade and subsidies.

More broadly, joining the E.U. would fulfill the vision of Mustafa Kemal Ataturk, the modernizing army general who created the modern Turkish republic out of the ruins of the Ottoman Empire in 1923. Ataturk, who is almost a deity in modern Turkey (his portrait adorns not only every government office but also almost every shop and home), wanted to modernize his country. Thus he substituted European hats and suits for fezzes and robes, and he adopted the Latin alphabet in place of Arabic letters. Having Turkey officially join the E.U., notwithstanding the fact that 95% of its territory is located in Asia, would be the ultimate affirmation of Kemalism.

The irony is that this is happening under a government whose outlook is sharply at odds with Ataturk’s. The ruling Justice and Development Party, led by Prime Minister Recep Tayip Erdogan, is an Islamic organization that opposes Ataturk’s militantly secular policies. It would, for instance, like to end the ban on women wearing head scarves in government buildings. In the past the military, which sees itself as the guarantor of Ataturk’s legacy, would not have hesitated to step in and topple a government that got out of line. Today, there’s much less chance of that happening because Turkey must adhere to democratic norms to enter the E.U.

Traditionally, America has been a close ally of Turkey and a strong supporter of its membership in the E.U. But as Turkey gets closer to that goal, a funny thing is happening: Its relationship with America has been getting more and more strained. Having spent last week speaking to a variety of audiences across Turkey in a lecture tour sponsored by the U.S. State Department, I’ve discovered that Turks are becoming positively Parisian in their disdain for America. Most Turks were violently opposed to the American invasion of Iraq, which they feared would lead to a separate Kurdish state, and nothing that’s happened since has led them to change their minds.

Last month’s assault on Fallujah induced paroxysms of rage here. Newspapers were full of imaginative claims about Americans using chemical, biological, even nuclear weapons. A leading Turkish parliamentarian accused the Marines of committing “a genocide [that] was never seen in the time of the pharaohs, nor of Hitler.” Far from trying to extinguish such inflammatory rhetoric, Erdogan added fuel to the fire by referring to the “hundreds of martyrs” killed in Iraq. The prime minister has also called into question the Turkey-Israel alliance by strongly condemning Israeli actions against terrorism – none of which exceed the harsh steps taken by the Turkish security services to put down a revolt by Kurdish separatists in the 1970s and 1980s.

The shift in tone on the part of the Turkish government can be attributed partly to the fact that Erdogan represents Sunni Muslims who are sympathetic to their co-religionists fighting Israeli and American “imperialism.” Washington is not blameless either; the Bush administration has not done a very good job of managing this international alliance or most others. But there is also widespread suspicion that Turkey feels compelled to adjust its traditionally pro-American attitudes to curry favor with anti-American E.U. members like France and Germany.

This might lead some Americans to wonder whether Turkish membership in the E.U. is such a good idea after all. It shouldn’t. Notwithstanding numerous trans-Atlantic squabbles, the E.U. is a positive force for integrating southern and eastern European countries firmly into the fold of the West, institutionalizing democracy, and opening up their closed economies. E.U. membership may be a bad deal for Britain, whose free market is hampered by heavy-handed regulations from Brussels, but it’s a positive force for change in Turkey, which still has a long way to go before it can enjoy British-style prosperity or stability.

What Americans should hope is that the E.U. will not make the process of integrating Turkey too long and drawn out. While Turkey remains outside the E.U., its face pressed to the glass, it will feel compelled to kowtow to the mandarins of Brussels, Paris, and Berlin. If it ever gets inside the door, it could afford to follow its own political path, as Poland, Britain, Italy, and other E.U. members already do. Memo to Brussels: If there’s one thing the fiercely nationalistic Turks can’t stand, it’s being told what do by outsiders.

Mr. Boot is a senior fellow at the Council on Foreign Relations and a columnist for the Los Angeles Times, where this first appeared.