EU needs Turkey for 2,500 foreign fighters fleeing Syria

Around 5,000 foreign fighters from Western Europe are believed to be fighting for the Islamic State of Iraq and the Levant (ISIL). 

As the fighting to oust ISIL from Iraq and Syria rages on, the whereabouts of these foreign fighters after the potential defeat of ISIL seems to have started to loom in the radar. That is especially the case for European countries contributing to the coalition forces that help the local forces' ground offensive via aerial support.

It is estimated that around half of the foreign fighters from Western Europe are likely to die in the war, but the other half will flee Syria to return to their respective countries after the defeat of ISIL. Which road will they be using? One route will certainly be through Turkey. 

Whether it is a curse or a blessing, Turkey's geographical location once again weighs heavily when it comes to Ankara-Brussels relations. 

President Recep Tayyip Erdoğan recently threatened to "open the gates" to refugees crossing to Europe. Does that blackmail include the threat that foreign fighters could also find safe passage to Europe? Regardless of what the intentions of Erdoğan may be, European capitals must certainly factor in this possibility. After all, even if it might not be Turkish government policy to turn a blind eye to foreign fighters fleeing Syria to Europe, intensive cooperation is required between Ankara and European capitals to minimize foreign fighters' "freedom of movement."

Can the Europeans secure the Turkish government's cooperation if the latter's perception is that Europe has a double standard when it comes to cooperation against the outlawed Kurdistan Workers' Party (PKK)?
European capitals have been careless (to say the least) in respecting Turkey's...