Why did Turkey shoot down a Russian aircraft on Tuesday? Ankara shares a 900km border with Syria, some of which is controlled by so-called Islamic State. Since 2011 Turkey has been dealing with jihadists and millions of refugees crossing its border, as well as the odd wayward rocket attack from Syria. Turkey says it warned a Russian jet 10 times in five minutes as it approached Turkish airspace. When it got no response it blew the aircraft out of the sky. As a member of Nato Turkey feels that it has the confidence to shoot down a foreign warplane – the first time such action has been taken against a Russian military jet since the Korean War – if it violates its airspace.
So is this a purely military matter? Not exactly. Inside Turkey, President Recep Tayyip Erdogan has purged the judiciary and police forces of potential opponents, sent journalists to prison and fuelled a return to war against the PKK Kurdish militant group. So it looks as if Erdogan is treating the Russians with the same amount of respect that he shows to his opponents at home – which is to say very little indeed.
Why are Russian warplanes in Syria? The Middle East has always been a place in which foreign powers meddle, and Russia's piece of the pie is anchored to a naval base it keeps in the Syrian port of Tartous. To stay relevant in the region (and to keep the West in check) it has nailed its flag to the regime of Syria's president, Bashar al-Assad. This has meant providing Assad with crucial diplomatic backing at the UN, along with weapons and warplanes. Backing Assad makes Moscow matter again, despite the former's barrel-bombing, shelling and torture of countless thousands of civilians.
What does Turkey want? Despite being friendly with Syria during the 2000s, Ankara called for Assad to step down early during the 2011 revolt. When the Syrian president didn't comply, Turkey turned a blind eye to anti-Assad rebels shipping weapons and fighters over its border into northern Syria. But in the intervening years Syrian Kurds – secular in outlook and capable fighters – have carved out chunks of territory inside northern Syria. Having battled separatist Kurds at home for more than 30 years, Ankara is frightened by the prospect of Kurdish autonomy playing out just over its border.
Are there any other factors? Adding to Turkey's headache is that some of the rebels whom Erdogan backed in 2012 are today the jihadists of Islamic State. The worst terrorist attack in Turkey's history, in which 103 people on a peace march in October were slaughtered, is thought to have been carried out by a Turkish Islamic State cell. But the ace up Erdogan's sleeve is his perceived ability to block refugees flooding into Europe. That makes him very useful to the old continent.
But aren't Kurds the good guys? They may be, but they've got few friends in this savage war. Turkey believes the Kurds, in Syria and at home, plan to establish their own state. Islamic State sees them as infidels to be slaughtered. The Assad regime has kept a foot to their collective throats for decades; the US and Europe depend on Turkey and Assad's supporters in Moscow to effect any potential for ending the war.
Sounds complicated. Any end to the war in sight? For now, no. The Syria conflict has made fools of the distinguished statesmen Kofi Annan and Lakhdar Brahimi; multiple missions deployed on the ground to monitor ceasefires have failed. The US president, Barack Obama, appears to have decided that it's too big a mess to solve, while other major players – the Syrian regime, Iran, Russia and the Lebanon-based Islamist group Hezbollah – are prepared to let things chug along. It may take a decade for the fighting to stop.