|Turkish activists have held protests for and against the Ergenekon affair [EPA]
Turkey has always been a country haunted by conspiracy theories – and not without reason.
Western powers nearly succeeded in dividing Turkey between themselves at the end of the Ottoman Empire ... and after the rise of the Soviet Union, new Nato member Turkey was on the frontline of the Cold War.
Conspiracy literature is a huge industry here: Books postulating improbable links between regional powers - even one series claiming Recep Tayyip Erdogan, the Turkish prime minister, is secretly Jewish and doing Israel's bidding - are best sellers.
But even by Turkish standards, the events unfolding in a special courthouse in Besiktas, central Istanbul, beggar belief.
Here, 49 very senior military figures, some retired and some - and this is a new and significant development - still on active duty, have been brought before special prosecutors to answer charges of involvement in a plot to destabilise the country and pave the way for another military coup.
The alleged plan for achieving this takeover involved a systematic exploitation of Turkey's history of antagonism and suspicion towards its ethnic and religious minorities, and a bombing campaign designed to cause significant numbers of civilian casualties.
It seems this was to be blamed on "Islamic terrorism", with the intention of showing up the government as being "soft" on the issue, and leading to a public outcry calling for the return of military rule.
The "threat" posed by neighbour Greece was also to be invoked, with a proposal to provoke a Greek airstrike on a Turkish fighter jet.
The principal "plot" which is the centre of the prosecutions here – called Balyoz or Sledgehammer – has not come out of the blue.
It was published by a fiercely independent Turkish newspaper, Taraf, on 20 January this year, and came in the wake of revelations in the same publication last November of another plot called Kafes, or Cage, that had even more detailed schemes for the re-establishment of military rule.
But Taraf reports were chiefly the product of a hefty series of leaked documents – the "plot literature".
The military has not denied they are theirs, but says they are merely hypothetical – the sort of "crisis scenarios" that security forces deal in.
The question is: Who leaked them? And: Why now?
Turkey is already in the midst of the most significant prosecution of supposed coup-plotters in its history.
Known as the "Ergenekon Trial", there have so far been nearly 200 hearings since October 20, 2008.
The evidence that forms the basis for this judicial process has been piling up since 2001, but only gained momentum in 2007 when - after a tip off - a small arms cache was discovered in the Istanbul suburb of Umraniye which - it is claimed - was linked to the "deep state".
Turks have always known they have many parallel actors in its government and security services, not all of which were legitimate or even widely known.
Bulent Ecevit, a former prime minister, broke the silence on the deep state in the 1970s, acknowledging that there were secret paramilitary operations working "within the government".
He much later admitted that even in office he was in the dark about what some of them were.
The investigations following the 2007 tip off has so far resulted in three sets of multiple indictments - with another one believed to be pending - hundred of arrests, and media-promoted revelations from sources such as tapped private phones.
The fact that some of these were of only tangential relevance to the prosecution, and that some of the evidential facts have been publicly disputed, has not helped maintain public confidence in the legal process.
The guiding philosophy of Turkey's secret operations was to maintain the strength of the country's secular state as founded by Mustafa Kemal Ataturk in the 1920s.
"In recent years, battle lines have been drawn between the secular/nationalist legacy of Ataturk and what some see as the rise of political Islam."
The means included many extrajudicial killings, assassination of people regarded as ideological or political threats, and the waging of numerous counter-terrorist operations against groups like the Kurdistan Workers' Party (PKK) who were viewed as a threat to the integrity of the Turkish nation.
Few, if any, of the orders and powers behind these actions have ever been examined in the public domain – or brought to justice.
There have been some official investigations, but few real conclusions and fewer prosecutions.
This is despite many campaigns by human rights groups and families of the victims.
The European Court of Human Rights in Strasbourg, France, has in fact made more rulings on these cases than the Turkish courts.
At the same time, the continuity of Ataturk's legacy was one of the justifications for the four military-led overthrows of the Turkish government since 1960.
The military have – to their supporters – been seen as a "reset button" to be activated when Turkish politics drifted too far from what it is believed Ataturk intended.
Increasingly in recent years, battle lines have been drawn between the secular/nationalist legacy of Ataturk and what some see as the rise of political Islam, embodied in its most successful version under the ruling AK Party, which was first elected in 2002.
The secular axis in Turkish politics – which in the past was led by the military – has tried repeatedly to limit what they see as a potential "Islamic threat".
Their ability to do this has diminished as Turkey's tolerance for military coups has waned with modernisation, and the ideal of religious and cultural freedom as something positive has grown.
But an attempt in 2008 to close down the government using the court system on the grounds that it was undermining Turkey's secular constitution, after it tried to lift the ban on women wearing head scarves in public institutions, only narrowly failed.
The government was instead "fined" $20m by the constitutional court.
Now it looks as if the tables are turning, and the civilian government in Ankara may be gaining the upper hand for the first time.
General Ilker Basbug, Turkey's military chief, accused the government in December 2009 of waging "asymmetic psychological warfare" against the military.
One AK Party deputy, Avni Dogan, declared on 20 February that "they blacklisted us for 40 years, now we are blacklisting them".
What seems to have changed, is that the government has sufficient allies in the civil service and the police, perhaps even now in the military, to run its own investigations into the activities of the deep state, and its perceived antagonists in the armed forces.
"It is entirely possible that Turkish military command is not completely aware any longer of what is going on within its own ranks."
The Turkish public is deeply divided about what to believe.
The country is split between those who believe the Ergenekon investigation is a long overdue clean-up of the deep state, and a move in the direction of a properly functioning democracy - while others are equally convinced it is a plot to overturn the legacy of Ataturk and establish an Islamic state in its place.
The Sledgehammer prosecutions – to them – are merely another stage in this process.
Even the country's judiciary is at odds over how to conduct these investigations – or even whether they should be conducted at all.
But by any reckoning, the events of the past week are politically seismic.
It is the first time that there have been large-scale arrests of such senior figures in the Turkish military, including not only retired officers who might otherwise be portrayed as belonging to another era of governance, but also serving members.
Prosecutors also appear to feel that in the shape of the Sledgehammer plot, they have something "actionable" – a tangible signed document that leads directly to senior military figures.
And the possibility that these documents came from military sources, may demonstrate a push for reform from within, as well as from outside.
It is entirely possible that the Turkish military command is no longer completely aware of what is going on within its own ranks.
Turkey is in new and unpredictable political territory here.