In the wake of the murderous attacks in Paris, we can expect western heads of state to do what they always do in such circumstances: declare total and unremitting war on those who brought it about. They don’t actually mean it. They’ve had the means to uproot and destroy Islamic State within their hands for over a year now. They’ve simply refused to make use of it. In fact, as the world watched leaders making statements of implacable resolve at the G20 summit in Antalaya, these same leaders are hobnobbing with Turkey’s president Recep Tayyip Erdoğan, a man whose tacit political, economic, and even military support contributed to ISIS’ ability to perpetrate the atrocities in Paris, not to mention an endless stream of atrocities inside the Middle East.

How could ISIS be eliminated? In the region, everyone knows. All it would really take would be to unleash the largely Kurdish forces of the YPG (Democratic Union party) in Syria, and PKK (Kurdistan Workers’ party) guerillas in Iraq and Turkey. These are, currently, the main forces actually fighting ISIS on the ground. They have proved extraordinarily militarily effective and oppose every aspect of ISIS’ reactionary ideology.

But instead, YPG-controlled territory in Syria finds itself placed under a total embargo by Turkey, and PKK forces are under continual bombardment by the Turkish air force. Not only has Erdoğan done almost everything he can to cripple the forces actually fighting ISIS; there is considerable evidence that his government has been at least tacitly aiding ISIS itself.

It might seem outrageous to suggest that a NATO member like Turkey would in any way support an organization that murders western civilians in cold blood. That would be like a NATO member supporting al-Qaida. But in fact there is reason to believe that Erdoğan’s government does support the Syrian branch of al-Qaida (Jabhat al-Nusra) too, along with any number of other rebel groups that share its conservative Islamist ideology. The Institute for the Study of Human Rights at Columbia University has compiled a long list of evidence of Turkish support for ISIS in Syria.

And then there are Erdoğan’s actual, stated positions. Back in August, the YPG, fresh from their victories in Kobani and Gire Spi, were poised to seize Jarablus, the last ISIS-held town on the Turkish border that the terror organization had been using to resupply its capital in Raqqa with weapons, materials, and recruits—ISIS supply lines pass directly through Turkey.

Commentators predicted that with Jarablus gone, Raqqa would soon follow. Erdoğan reacted by declaring Jarablus a “red line”: if the Kurds attacked, his forces would intervene militarily—against the YPG. So Jarablus remains in terrorist hands to this day, under de facto Turkish military protection.

How has Erdoğan got away with this? Mainly by claiming those fighting ISIS are “terrorists” themselves. It is true that the PKK did fight a sometimes ugly guerilla war with Turkey in the 1990s, which resulted in it being placed on the international terror list. For the last ten years, however, it has completely shifted strategy, renouncing separatism and adopting a strict policy of never harming civilians. The PKK was responsible for rescuing thousands of Yazidi civilians threatened with genocide by ISIS in 2014, and its sister organization, the YPG, of protecting Christian communities in Syria as well. Their strategy focuses on pursuing peace talks with the government, while encouraging local democratic autonomy in Kurdish areas under the aegis of the HDP, originally a nationalist political party, which has reinvented itself as a voice of a pan-Turkish democratic left.

They have proved extraordinarily militarily effective and with their embrace of grassroots democracy and women’s rights, oppose every aspect of ISIS’ reactionary ideology. In June, HDP success at the polls denied Erdoğan his parliamentary majority. Erdoğan’s response was ingenious. He called for new elections, declared he was “going to war” with ISIS, made one token symbolic attack on them and then proceeded to unleash the full force of his military against PKK forces in Turkey and Iraq, while denouncing the HDP as “terrorist supporters” for their association with them.

There followed a series of increasingly bloody terrorist bombings inside Turkey—in the cities of Diyarbakir, Suruc, and, finally, Ankara—attacks attributed to ISIS but which, for some mysterious reason, only ever seemed to target civilian activists associated with the HDP. Victims have repeatedly reported police preventing ambulances evacuating the wounded, or even opening fire on survivors with tear gas.

As a result, the HDP gave up even holding political rallies in the weeks leading up to new elections in November for fear of mass murder, and enough HDP voters failed to show up at the polls that Erdoğan’s party secured a majority in parliament.

The exact relationship between Erdoğan’s government and ISIS may be subject to debate; but of some things we can be relatively certain. Had Turkey placed the same kind of absolute blockade on ISIS territories as they did on Kurdish-held parts of Syria, let alone shown the same sort of “benign neglect” towards the PKK and YPG that they have been offering to ISIS, that blood-stained “caliphate” would long since have collapsed—and arguably, the Paris attacks may never have happened. And if Turkey were to do the same today, ISIS would probably collapse in a matter of months. Yet has a single western leader called on Erdoğan to do this?

The next time you hear one of those politicians declaring the need to crack down on civil liberties or immigrant rights because of the need for absolute “war” against terrorism, bear all this in mind. Their resolve is exactly as “absolute” as it is politically convenient. Turkey, after all, is a “strategic ally.” So after their declaration, they are likely to head off to share a friendly cup of tea with the very man who makes it possible for ISIS to continue to exist.

[This article first appeared on the Guardian’s “Comment Is Free” site.]