The heinous terror attack in the heart of Istanbul, targeting more than 500 guests celebrating New Year’s Eve in a popular nightclub on the Bosphorus, marked the peak of a series of massacres that has shaken Turkey to its core over the past year. These have partly been attacks against security forces claimed by offshoots of the Kurdistan Workers’ party (PKK); and partly attacks by jihadi groups, imported from Syria.

The bloodbath has now been claimed by Islamic State. But – and it is a big but – there was a particular significance to the target. Jihadi terror has previously targeted Kurds, Alevis and leftists in Turkey, leaving hundreds dead. But, for the first time, a venue representing the secular lifestyle of the urban upper-middle classes was chosen. And the attack came at a critical time when Turkey’s ruling AKP party had made the basic secular tenet of republican Turkey vulnerable.

Weeks before New Year’s Eve, banners were hung by pro-government Islamist organisations in Turkey’s cities, telling people that “Muslims don’t celebrate Christmas”, followed by photos depicting groups of young men in local dress, chasing Santa Claus with guns and knives.

The icing on the cake was the sermon by Turkey’s powerful directorate of religious affairs (Diyanet) – which represents the pious Sunni majority (roughly 70% of Turkey’s population), though it is financed by all taxpayers.

The statement told Turks not to waste money on new year celebrations. Secular Turks saw it as an undue intrusion on their lifestyles. But the sermon had already encouraged widespread hate speech on social media in the final days of 2016, including death threats towards those planning to celebrate New Year’s Eve. (For this reason, Mehmet Sönmez, the head of Diyanet, is now being asked to resign by the pro-Kurdish HDP party for “incitement to hatred”, probably to no avail.)

Remarkably, no minister or bureaucrat has resigned; nor were any removed from their posts, despite the fact that the death toll of the seemingly endless series of terror attacks since July 2015 – when the Turkish president Recep Tayyip Erdo?an terminated peace talks with the PKK Kurdish militant group in reaction to PKK-linked violence – has risen to nearly 1,800, out of which more than 600 are civilians. The government’s arrogant disregard of calls for resignations raises suspicions that the AKP will never leave power peacefully, adding to the tension felt by many Turkish people.

While Turkey has seen several mass killings over the past 18 months, it was during the second half of 2016 that the acts of terror somehow became routine: while the PKK targeted security forces en masse, jihadi terror crept into major urban areas. The pattern clearly shows that the state’s intelligence network is now at its weakest.

Observers claim there is a correlation with a massive purge of the security apparatus that Erdo?an launched before the failed coup of July 2015. The ruling AKP blamed that exclusively on military officers affiliated with Fethullah Gülen, a reclusive cleric based in Pennsylvania, although outside experts largely question this official narrative. This “institutional cleansing” of otherwise highly qualified officers who were indiscriminately labelled as Gülenists led to hasty replacements. The suspicions are that their posts were filled by recruits sympathetic to jihadi movements, or, at best, people unqualified for the job. The Turkish state’s security deficit leaves the country vulnerable to further acts of destruction.

The terror in Istanbul left few in doubt over the connection with Syria. Less than 24 hours after the massacre, it was Numan Kurtulmu?, the deputy prime minister and spokesman of the AKP government, who said: “It is a message against Turkish cross-border operations. The operations in Syria obviously stirred unease among terror organisations. We will take measures at home and across the border.”

The deadly equation is apparent. Once seen as a “regime changer” in Syria, Turkey has long been far too supportive of murky elements of radical Islamism, partly in an attempt to realise a neo-Ottoman dream of turning Syria into a Sunni-dominated hinterland and partly to use them in a combat to prevent Syrian Kurds to establish autonomy on the Turkey-Syrian border. And now, Turkey has fully reversed its Syria policy, ceasing its logistical support for the Syrian opposition to Bashar al-Assad, as a result of shrewd Russian moves and the assassination of the Russian ambassador in Ankara.

Turkey will inevitably come into greater conflict with Isis and al-Qaida elements from now on. Murder in Ankara and the bloodbath in Istanbul may only be overtures that tear apart Turkey’s already explosive social faultlines. The battle of al-Bab, and the imminent siege of Idlib, both very close to the Turkish border, promise more trouble ahead.