Letter from Istanbul/ Nicholas Birch: An increasingly bitter row over Islamic extremism has left Turkey polarised and this secular Muslim country's hard-won economic and political stability looking increasingly under threat.
The overt trigger to trouble was a speech made in April by Ahmet Necdet Sezer, Turkey's president, who warned military officers that "the fundamentalist threat has reached alarming proportions". A stickler for Turkey's peculiar brand of secularism, Mr Sezer is not a natural friend of the self-styled "Muslim democrats" who swept the board at parliamentary elections in 2002.
Relations between him and the Justice and Development (AKP) government have been frosty since he banned the headscarf-wearing wives of lawmakers from state receptions three years ago. Since then, he has vetoed hundreds of government bureaucratic nominees on suspicions of being too close to political Islam. His recent talk of "fundamentalists [ attempting] to infiltrate politics, education and the state" is nonetheless a departure from his usual verbal moderation.
For a man supposed to be above party politics, so is his choice of venue: Istanbul's war academy. The author of three coups since 1960, Turkey's army last intervened in 1997 to edge an Islamically-minded government from power.
The change of tone has been paralleled by the Turkish press. Barely a day goes by now without Islamist misdemeanours making headlines: men and women sitting separately at a local governing party congress, an AKP municipality handing newly-weds booklets describing Muslim attitudes to marriage.
A survey published this week counted 187 newspaper articles about "reactionaries" - the semi-official Turkish term for Islamists - this January. In April, the number had increased to 858.
"Does the fourfold increase reflect increased concern among ordinary people, or has the issue been forced?" Ekrem Dumanli, editor of the moderate religious daily Zaman, asks. His scepticism is shared by political analyst Cengiz Candar, who sees the ongoing row as the first broadside in a political war over who will replace Mr Sezer as president next spring.
"For an essentially symbolic post in a system where the prime minister is the real head of the executive body, it might seem amazing that competition is [ already] so acute," he notes.
The reasons are nonetheless clear. It is parliament which elects presidents in Turkey. Unless parliamentary elections due next year are brought forward, AKP will be able to use its huge current majority next spring to select someone of its choice.
Prime Minister Tayyip Erdogan is thought to be keen on the post.
It's a prospect that is intolerable to Turkey's more hawkish secularists, who interpret any expression of religious identity as a threat to the state. The thought that the secular republic might soon be represented by a man whose wife wears a headscarf horrifies them.
More importantly, though, they are afraid of the influence Mr Erdogan could wield if elected.
Though Turkey's is not a presidential system, presidents act like a weak upper chamber, delaying and distorting legislation. Once they are in charge of both legislative organs, many secularists argue, AKP's cohorts will drop their reformist, pro-European discourse in favour of full-on political Islam.
One of Turkey's prominent journalists, Taha Akyol, thinks the fear is misplaced. "If Mr Sezer were to get out of [ his presidential palace] and listen a little to social scientists who have analysed Turkey's accelerating process of social secularisation, he wouldn't be quite so worried," he argues. "But his beliefs prevent that."
Quite so. As tensions rise, political debate has increasingly come to resemble a dialogue of the deaf.
When AKP's parliamentary speaker, Bulent Arinc, advocated US-style secularism over the more combative French version currently in operation, secularist opposition members labelled him "Bulendinejad", a reference to Iran's hardline president.
The debate got even uglier last week, when a former prime minister and president taunted the government for its failure to resolve the headscarf issue. "They should go and study in Saudi Arabia," Suleyman Demirel said, referring to the headscarf-wearing students who have been banned from universities since 1998.
Beyond the increasing barrage of criticism, it is difficult to see what Turkey's secularists can do to block the AKP.
Following Mr Demirel's remarks, some are hoping this former bête noire of Turkey's secularists will make a political comeback to lead a multi-party coalition against the AKP.
Others, covertly or overtly, are calling for the army to step in. Political scientist Sahin Alpay thinks that's very unlikely to happen. "Turkey has come a long way since February 28th," he says, referring to the 1998 resignation of an Islamist government following an ultimatum from the army.