August 20, 2015 | The Wall Street Journal

Turkey Awakens to the Islamic State Threat Within

News reports over the weekend revealed that Turkish police recently discovered 30 suicide vests, some ready for immediate use, in raids against the Islamic State. The news came one week after an Islamic State social-media account threatened the Turks with an imminent attack. Accusing Turkey’s government of “standing with the crusaders and spilling Muslim blood,” the group warned that the Turkish people would be the ones paying the price for their leaders’ war on the caliphate. Reuters reported this week that a new video calls for the group to conquer Istanbul.

A U.S.-led coalition has been striking Islamic State targets for a year, but Ankara only recently joined the fight. Turkey’s main objection to the coalition had been the lack of a comprehensive strategy for the crisis in Syria. It correctly views Islamic State as merely a symptom of Syria’s civil war, and believes the only lasting solution is the removal of Syria’s president, Bashar Assad. Turkey has called for military intervention against Mr. Assad for four years and fears that the coalition’s effort to weaken Islamic State could end up bolstering the very regime Ankara seeks to upend.

But Turkey has also been reticent for fear of reprisals. Although Islamic State has been entrenched across Turkey’s Syrian border since January 2014, Ankara has until recently managed to keep the group at bay.

That Turkey stayed out of the fray for this long is remarkable. The steady flow of fighters, weapons and cash from Turkey to the front might have been one way of placating the jihadists across the border. The fact that middlemen in Turkey have been purchasing oil and antiquities from Islamic State merchants may also have helped keep things quiet.

True, Islamic State terrorists attacked two Turkish security officials last year, kidnapped 49 Turkish diplomatic staff and threatened troops guarding an Ottoman tomb in Syria. But Ankara cut a prisoner-exchange deal with the caliphate for the diplomatic hostages and safely evacuated the soldiers from the tomb in a daring operation.

Until last month, Islamic State had not conducted a mass-casualty attack on Turkish soil. Then on July 20 a suicide bomb in the southeastern border town of Suruc killed 33 civilians and wounded 100. Islamic State didn’t claim responsibility for the attack, but the government insisted that the terrorist, a Turkish Kurd, had links to the group. (Ankara has yet to provide concrete proof.) Cross-border gunfire and airstrikes ensued, marking Turkey’s first direct confrontation with Islamic State.

In recent weeks, Ankara has beefed up its military presence along its Syrian border and announced plans to build a wall along its eastern frontier. Still, Turkey appears unwilling to take seriously the possibility of an Islamic State threat from within. Antiterror police arrested more than 2,500 suspected terrorists across Turkey last month. Fewer than 100 of those were reported to be linked to Islamic State, and only 22% of those were charged. This isn’t enough to deter Islamic State from conducting attacks there.

The potential for a domestic strike is real. Islamic State has been active in Turkey for almost as long as the group has been fighting in Syria. Until it began to feel the squeeze from the West in September, Ankara not only permitted the group to grow financially and militarily across its border, but also allowed the group to establish networks throughout Turkey and even recruit Turkish citizens.

A leaked January police report warned of at least 3,000 Islamic State operatives living in Turkey and “sleeper cells” in cities such as Adana, Ankara, Gaziantep, Istanbul and Konya. Other Turkish and Western media reports revealed Islamic State recruitment in cities throughout the country via foundations and mosques. Turkish magazines and websites sympathetic to Islamic State have bolstered the group’s domestic support, though courts began shutting down the sites last month.

Then there are the returning jihadists. Hundreds of Turkish citizens have fought with Islamic State in Syria, according to U.S. military estimates, and many of them have returned home. Two former Islamic State fighters have already carried out attacks in Turkey this summer—in the Suruc attack, and in the June bombing of a pro-Kurdish rally in Diyarbakir.

Even the most hardened Islamic State fighters are able to freely walk the streets, former Turkish military advisor Metin Gurcan notes, thanks to a legal loophole: They can’t be convicted unless they have committed violence on Turkish soil.

With the recent collapse of the two-year cease-fire between Turkey and the Kurdish terrorist group Kurdistan Worker’s Party, or PKK, Ankara has been focused on combatting the PKK. That’s a misplaced priority. The PKK will almost certainly declare another cease-fire and return to the negotiating table. Islamic State, by contrast, has nothing to negotiate with a NATO country that allows Washington to fly sorties from its territory.

The group is still entrenched across the border, and the battle lines are drawn. With its operatives and sympathizers positioned throughout the country, Islamic State attacks are a serious threat to Turkey.

Mr. Schanzer is vice president for research at the Foundation for Defense of Democracies. Find him on Twitter: @Jschanzer 

Ms. Tahiroglu is a research associate at the Foundation for Defense of Democracies. Find her on Twitter: @MerveTahiroglu

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