...And was there any truth in Putin’s accusation yesterday — made just as Moscow was expelling 39 Turkish businessmen attending a conference in Russia — that Turkey is propping up ISIS by buying oil from them?

This latest claim inevitably prompted a furious response from Erdogan, who accused Putin of slander. But the fact is that Erdogan’s regime has on many occasions turned a blind eye to ISIS activity in Turkey, as well as to Turkish businessmen and smugglers doing trade deals with the jihadist butchers.

To be fair, on the surface, Turkey’s president is fully involved in the fight against ISIS. In October he allowed U.S. jets to use Turkey’s Incirlik air base for operations against ISIS, pledging that his forces, too, would join the fight.

But the truth is that Turkey’s planes have aimed their missiles almost exclusively at the one army which poses a real threat to ISIS, and has won countless battlefield victories against them — the Kurdish PKK forces inside Syria.

The trouble is that Erdogan, who has spent years ruthlessly concentrating power into his own hands, considers the Kurds an even greater threat to his nation than ISIS....