The day I arrived in Istanbul, they buried the last Ottoman. Her Imperial Highness Fatma Neslisah Sultan had been born in a royal palace overlooking the Bosphorus when her grandfather still notionally reigned over the remnants of a vast, intercontinental realm. The day after I left, gunfire from Syrian president Bashar al-Assad's troops killed several people inside Turkey. Their shots crossed a frontier that did not exist until the demise of the Ottoman empire.
On the face of it, these two events seem quite unrelated: the first, a mere historical curiosity, the second, among the most urgent political and humanitarian challenges of the day. Upwards of 9,000 people have now reportedly been killed in Syria. Tens of thousands more have been wounded and, according to some estimates, up to a million men, women and children are internally or externally displaced. French and British-led intervention in Libya was triggered by Muammar Gaddafi's credible threat to kill civilians in Benghazi en masse. Assad has actually done it in Homs.
At the time of writing, he has ignored the deadline agreed with former UN general secretary Kofi Annan for the withdrawal of Syrian forces. The chances of an effective ceasefire seem vanishingly small. If the scale of mass killing of civilians were the sole trigger for humanitarian intervention, we should have done it weeks ago.
Yet these horrors and the passing of that last scion of empire are more closely related than you might think. For Turkey, it makes a world of difference that the territory now called Syria was, until the first world war, as much an integral part of the Ottoman realm as Ireland was of the British. This historical awareness is especially important for Turkey's moderate Islamist government, whose deputy prime minister attended the funeral ceremony for the last granddaughter of the last sultan. Its doctrine of "strategic depth" sees Turkey as a regional power, straddling Europe, the Middle East and Central Asia, like … guess who.
Its voluble and hyper-energetic foreign minister, Ahmet Davutoglu, has, to be sure, formally rejected the charge that he is a "neo-Ottoman"; but he has also said "I am not a minister of a nation state only". A former university professor, he talks often, eloquently, and at length about the Ottoman legacy. After one such performance, delivered to assembled foreign ministers of the European Union, one of them joked that the EU was being invited to join the Ottoman empire. But this is, of course, a modernised, slimmed-down, republican version, rather as the last princess ended her life officially called plain Mrs Osmanoglu – that is, roughly, Mrs Ottoman. (Think Mrs Windsor, formerly of Windsor Castle, in the British republic that I shall not live to see.)
More materially, the dynamic Turkish economy has major business and trading interests in Syria, while the chequerboard ethnic legacy of the partitioned Ottoman realms means that restless Kurds live on both sides of that Turkish-Syrian frontier. Not to mention the sheer, immediate pressure of refugees, which has led to increasing talk of the Turkish army imposing a buffer zone or humanitarian corridor inside the Syrian frontier. Some even suggest that Turkey could cite a violation of article 1 of the 1998 Adana agreement between the two countries, which states that "Syria … will not permit any activity that emanates from its territory aimed at jeopardising the security and stability of Turkey". (This originally referred to support for Kurdish groups such as the PKK.) In Istanbul, I also heard unconfirmed reports of former members of Turkish special forces fighting with the Free Syrian Army.
But there's a larger story here. When I write, in relation to humanitarian intervention, "we should have done it long ago", many readers' default assumption will be that my "we" refers mainly to western powers, preferably acting with some UN authority and politely called "the international community". And it is true that if the west's leading military powers, above all the US, then Britain and France, do engage with armed force – as they eventually did in two other unhappy corners of the former Ottoman empire, Bosnia and Kosovo – that has a transformative effect. But none of them, least of all Washington, show any intention of doing so here.
US president Barack Obama and French president Nicolas Sarkozy have elections to win. British prime minister David Cameron is too busy eating cold pasties and drumming up trade in the Far East. They will express outrage, and try to ratchet up economic sanctions and diplomatic pressure through the UN, but don't expect any Libya or Kosovo-type intervention any time soon.
In these circumstances, it is other powers that will determine the fate of the Syrian people. In the near future, Turkey will be more important than Britain, Iran than Germany, Saudi Arabia than France, Russia than America. In Syria, all these regional powers pursue their own national interests, defined not just in economic and military but also in cultural and ideological terms. So there's a struggle between Shia, post-revolutionary Iran and Sunni, reactionary Saudi Arabia, post-imperial Russia and neo-Ottoman Turkey, not to mention distant but mighty China – a vital swing vote among the permanent members of the UN security council.
If some weary pasha had gone to sleep in 1912 and only woken up today there would of course be much to surprise him, from post-colonial states to Facebook, democracy and mobile phones. But after a few weeks of adjustment, he might feel quite at home. Ah yes, he would say, here are great powers pursuing their very different values and interests, openly and by stealth, in the familiar great game. In fact, many of them are reduced, partially modernised versions of the same old powers: Turkey now under sultan Recep Tayyip Erdogan, Russia yoked to tsar Vladimir Putin, China in the last months of emperor Hu Jintao, Britain with Her Majesty's pink-cheeked first minister, and so on.
The balance of forces around Syria would be different if the historically new, shared sovereignty model of the EU had reached out to embrace Turkey, as it has been promising to do – incredibly, in both senses of the word – for nearly 50 years, since the association agreement of 1963. But it has not. Europe, as Europe, is inaudible on Syria as on so many other issues. And so the fate of that country's brave resisters and suffering civilians depends on the old-fashioned regional competition of diverse sovereign powers.
Timothy Garton Ash is a historian, political writer and Guardian columnist.