The stakes are high - a stable Turkey is essential to the West
Last Friday night my Ryanair flight arrived into Zadar airport in Croatia just before midnight. The plane was full of young Irish people pretty well tanked up on their way to the Ultra Music Festival in Split.
Everyone was in good spirits despite the rocky descent. The unexpected Adriatic storm is part and parcel of summer in this part of the world. The storms are both violent and swift. The burst of applause as we slammed, rather than touched, down was tinged more with relief than celebration.
My phone immediately started to beep with WhatsApp messages from a dear friend in Turkey. She was distraught.
"What are you hearing outside?"
"There's been a coup here. We don't know what to do."
"I'm so afraid for us."
This woman is a very successful businesswoman in Istanbul. She doesn't particularly like President Erdogan. Her hero is the remarkable Kemal Ataturk, the man who modernised Turkey and made it secular.
Even though the Turkish army regards itself as the upholder of the Kemalist tradition, and although she would normally side with anything secular against the increasingly Islamist government of Erdogan, she realised that once a country falls into the hands of the military, a civil war isn't far off. And a religious civil war is part, but not all, of the awful story of Syria.
The news of the coup and the realisation that it had failed - but only just - is a huge shock to anyone who has experienced modern Turkey, especially those of us who have worked in Istanbul in recent years.
Last year, I had the opportunity to work there for a large international company and was beguiled by the place. Istanbul is one of the world's great cities and there is evidence everywhere that this place has been at the centre of the world for close to 2,000 years, stretching down the ages from the Roman Eastern Empire to the days of the Ottoman Empire. The Ottomans were eventually deposed and replaced by Ataturk and his extraordinary secular vision in the early 20th century. He fashioned the new Republic out of the twin ingredients of science and nationalism.
Over the years, the city has been home to Jews, Greeks, Slavs, Armenians and Georgians, as well as the Muslim Turk population.
It has been one of the three great Muslim caliphates, the centre of the flourishing sophistication of the Christian Orthodox Church at a time when Rome was home to barbarians, and it was also the site of Judaism's finest synagogues.
You can see the imprint of all these great tribes in the architecture, the places of worship and the markets. You can feel the 19th-century European aspirations of the Ottoman merchant class in the wide, French-designed boulevards, but its narrow, higgledy-piggledly lanes tell you this isn't Paris, London or Berlin. It smells of the Orient, yet large parts look like the West. This is the echo of all who have passed through, set up home and then moved on again.
Most of the Greeks, Jews and Armenians left in the 20th century.
However, one constant has been the Bosporus Strait, linking the Black Sea and the Mediterranean. For thousands of years, this was the single most important trading route in the world, and even today it still feels like this. Every morning from my hotel, I looked out over the strait watching massive Russian cargo ships relentlessly ploughing through it, heading from the Black Sea to the Mediterranean.
This is where East meets West.
Is it any wonder that the coup plotters' first move was to close the Strait?
The congestion on the Strait is amazing to see. Just outside its mouth, close to the Dardanelles, where thousands of Irish troops died 100 years ago this year, there is a daily queue of ships waiting to get through.
The Irish were the first troops who landed in Gallipoli. To put the futility and slaughter in context, the Royal Dublin Fusiliers and the Royal Munster Fusiliers were the first to attack the Turks from the SS River Clyde. Of the first 200 men to leave the ship, 149 were killed and 30 wounded immediately.
This was always a strategic spot.
From that point in Gallipoli to the far side in the Black Sea, there is a constant flow of enormous, laden-down hulls carving slowly through the waters, reinforcing the proximity of the eastern part of Europe and the West. All sorts of Russian, Ukrainian, Crimean and, of course, Romanian and Bulgarian cargo ships use the Black Sea. And coming the other way are all sorts of manufactured products from southern Europe and North Africa.
Here you appreciate that this massive country of 80 million people is a huge regional power. Istanbul is Europe's largest city, home to close to 17 million people. Turkey's military is the largest in the region and there will be no settlement in Syria and Iraq without Ankara's imprimatur.
Under Erdogan, the economy grew strongly, inequality shrank and Turkish companies became regional powerhouses. Erdogan has restructured the economy and attracted more foreign investment in a decade than in the entire 90-year history of the Turkish Republic.
But two years ago, the Turkish economic miracle came to an abrupt end with political violence in the streets of Istanbul, Izmir and Ankara. The currency went into free-fall, as did the stock market.
Once the economy fractured, old alliances went the same way.
For years, Erdogan had as an ally an Islamist power base known as Gulenists - followers of a cleric called Fathullah Gulen, who is in self-imposed-exile. To the outsider, it seems a bit like an Islamic version of Opus Dei.
Originally, Gulen set up an educational system of strict religious schools, which taught a mixture of self-discipline, Islam and societal responsibility.
Many thousands of graduates of these schools - Gulenists - are now in powerful positions. Until recently, they were in cahoots with Erdogan in his 'soft Islam' project. This is the aspiration to combine an Islamic society living side-by-side with democracy and the constitutional protection of secularism.
Like all aspirations, the success of such a venture depends in significant measure on the economy being strong, offering opportunity and generating wealth.
As the economy turned down, this alliance turned sour.
Many believe that Gulen was behind the coup, signalling to his fifth column of supporters in the military to rise up. Others think it was a set-up by the government to bolster its own position. Whatever the real cause, Turkey won't be the same again. Turkey is the key country in the region. The US and the EU should be worried because if Turkey fractures, so too does the West's biggest regional ally, which stands between Russia, Iran and the unravelling Middle East.
The stakes couldn't be higher.