A glance at the map of the West's current crises shows that Turkey occupies the neuralgic point where so many international problems meet.It is the intersection of the West's war with Isil in Syria and Iraq. Nato's concerns about a resurgent Russia loom across the Black Sea. Oil and gas pipelines from the Caspian and beyond crisscross the region.And while the migration crisis may seem to be on the back-burner today, last year's exodus via Turkey to the EU showed that it could be easily reactivated as the launching pad for a renewed destabilising wave of refugees.For decades the US and its European allies got used to relying on Turkey as a bastion of their interests.Ironically, as democracy seemed to bed down in Turkey over the past 14 years under its president, Recep Tayyip Erdogan - who is now firmly back in control of the country after the failed military coup - the unpredictability of Turkey only grew.Erdogan has always been irked at being treated like a junior partner. A self-made man, he is very sensitive to snubs - and unforgiving. He came up from the bottom of Turkish society against all the odds to defeat his European- and US-educated opponents in the secular elite again and again.His chip-on-the-shoulder style appeals to his base but makes for an awkward partner for the international community.After years of touting himself as the man who would lead Turkey into the EU, Erdogan has soured suddenly on the idea. Last year his country acted as the funnel for mass migration from the Middle East into the EU, so Brussels came cap (or rather, chequebook) in hand to him. Erdogan showed he could turn off the tap if Brussels played ball with him.But since Brexit, the growing suspicion in Ankara that Turkey would never be welcomed into the Euro-club has become accepted fact.Stalking away from these ambitions, Erdogan suddenly launched a dramatic diplomatic revolution in the month before the coup. In rapid succession, his government repaired its relations with Russia, Egypt and Israel.Overnight Erdogan's descriptions of Putin, Sisi and Netanyahu as murderers were forgotten. Then, on the eve of the coup, Turkey's new prime minister even talked of reviving relations with Syria. At the same time, relations with the US have taken a nosedive.The Pentagon was taken by surprise when the Turkish government included US planes and drones operating out of their Incirlik airbase against Isil in Syria in the "no-fly zone" imposed over Turkey following the coup. Worse still, electricity was cut off to the base. Then the Turkish base commander was arrested, which sparked a flurry of rumours in Turkey that he was the "link-man" between the putschists and the Pentagon.That may be dismissed out of hand abroad, but it is a symptom of how alienated Erdogan's support base is from its US ally.Erdogan's immediate claim that the putsch was plotted by Fethullah Gülen, who is living in the US, added to the tension with Washington.John Kerry, the Secretary of State, has tried to be emollient by suggesting if Ankara has evidence against Gülen then he could be extradited in the normal way. But the State Department has also asked the Turkish authorities to deny charges that the US was in some way involved in the plot. Silence has met that request so far.Noting that Washington has warmed to neighbouring Iran - which Erdogan, as an orthodox Sunni, views as being run by "schismatics" - the president is now presenting himself to Israel as a natural ally against its Shiite mortal enemy and Iran's allies in the crescent from Teheran to Hizbollah in Beirut. The failed coup has not only increased the sense of instability inside Turkey.It has reinforced the factors that have made Erdogan's Turkey an increasing source of, and catalyst for, uncertainty in the sensitive regions around it.If Erdogan's rapprochement with the Kremlin leads him to block support for all Syrian rebels, and not just the West's bête noire, Isil, then a key factor in the US strategy to counter terrorism will go up in smoke.After decades of trying to join the West, it may be that he is prepared to exit it if Washington and the rest of us don't play ball.If Brexit has put Europe's stability into question, then a "Texit" from the West would shatter it. Certainly Erdogan is playing with fire. But that is something at which he is accomplished. Although the West's leaders shy away from the flame, Turkey's crisis is not an internal matter.Like it or not, the shock waves of its political infighting are going to wash across Europe and the Middle East. Erdogan won't be able to control them once they flow out of Turkey. But the West seems unlikely to step into the breach. - ©The Daily Telegraph..