“I cover my head, not my brain,” the Turkish First Lady tells The Times, her head swathed in white silk. But Harunisa Gül does not believe headscarves should be forced on women, and it would be hard to find anyone in Istanbul who disagreed with her - at least in public.

Ever since Mustafa Kemal Atatürk tranformed the remnants of the Ottoman Empire into a unitary state, compulsion in matters of dress has existed precisely to suppress signs of religion: Atatürk banned fezzes as well as veils. But 85 years on, headscarves are back, worn by perhaps 60 per cent of women. As in France, where a Muslim minister has denied a Muslim woman citizenship for wearing a niqab, they arouse the primal suspicions of an avowedly secular state. But in Turkey the headscarf means more. It has become the most potent symbol of a battle for the soul of the country that will determine its place in Europe and the Islamic world.

For her meeting with Janice Turner, of times2, Mrs Gül was a picture of cheerful optimism. Yet if the judiciary that regards itself as custodian of Turkish secularism has its way, she will not be First Lady for much longer. Despite the solid parliamentary majority that enabled her husband to become President, the country's Constitutional Court is determined to press ahead with a case intended to outlaw the ruling Justice and Development Party (AKP) and ban its leading members from politics.

Western governments must see this case for what it is - an attempted judicial coup. It has scant legal basis. If successful it would derail Turkey's already fraught EU accession and lead many AKP supporters to despair of the ballot box. The large-scale arrests this month of suspected conspirators, including senior army generals, have been condemned by some as arbitrary and authoritarian. They are better understood as self-defence by an endangered democracy.

But not all Turkey's secularists are putschists. As we report today, much of the country's educated middle class is genuinely alarmed by what it sees as creeping Islamism on the AKP's watch. Mrs Gül's decision in May to meet the Queen wearing a headscarf was merely a trigger for their indignation. Far more worrying is the idea that Islamic dress may imperceptibly become a matter of expectation rather than choice; that this expectation could lead to segregation of the sexes; and that such segregation could eventually be enforced by a legislature and bureaucracy packed increasingly with AKP supporters.

If Recep Tayyip Erdogan, the Prime Minister, is a stealth Islamist, he hides it well. Most available evidence suggests he is, in fact, a hard-nosed politician, committed to Europe, who believes in democracy because it has brought him power and who is devoutly Muslim.

Some of Mr Erdogan's critics are indignant generals as hostile to Europe and democracy as they are to Islam. But he needs to recognise that others are highly educated urbanites and intellectuals who are as integral to Turkey's identity and prosperity as is its Anatolian hinterland. He needs to keep them onside, not least by ensuring that public sector appointments are transparently on merit. For at stake here is nothing less than respect for democracy, for people of religion and for people who cherish the right to live lives absent of faith.