Turkey still has not sealed ISIL supply routes through its territory

Wall Street Journal:

The Obama administration is pressing Turkey to deploy thousands of additional troops along its border with Syria to cordon off a 60-mile stretch of frontier that U.S. officials say is used by Islamic State to move foreign fighters in and out of the war zone.

The U.S. hasn’t officially requested a specific number of soldiers. Pentagon officials estimated that it could take as many as 30,000 to seal the border on the Turkish side for a broader humanitarian mission. Cordoning off just one section alone could take 10,000 or more, one official estimated.

It’s unclear how Turkey will respond. Turkish officials said they agree that tighter border control is necessary, and have begun implementing some measures. They suggested that the Pentagon troop estimates are inflated, but declined to give a number of their own.

In return for doing more to fight Islamic State, Turkey is seeking more financial help from Europe to deal with its 2.2 million Syrian refugees, as well as support for a safe zone in Syria—an idea that has been shelved by the Obama administration as too risky and complicated.

U.S. officials say a bigger Turkish border deployment—including infantry and artillery units—would be the most realistic way to close off key transit routes on which Islamic State fighters in Syria rely and stem the flow of foreign fighters into Europe.
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That this has not been done is a sign of the lack of seriousness of the Erdogan government in Turkey to actually shut down ISIL.  I suspect they have not shut the border down because they are making money from the black market purchase of ISIL oil and selling them commodities which they use to sustain their operations.  If Turkey were really serious about closing the border it is likely that the refugee problem would be minimized with the defeat of ISIL.