A difficult ally

The "Islamic State" (IS) militia is encroaching on the Syrian city of Kobani near the Turkish border. People on the Turkish side can already see their black flags waving.

Kobani stands to lose its Kurdish civilians in a bloodbath perpetrated by IS, in plain view of the Turkish military. But so far, Turkey has done nothing to stop it. Its parliament has already made a decision: President Recep Tayyip Erdogan could deploy the Turkish army to Syria at any time to fight the IS militants. But he is hesitating.

Turkey, a member of NATO, has the most extensive ground forces in the alliance after the United States. Its forces could provide the ideal complement to US air strikes. Experts also agree that there is little point in fighting IS without troops on the ground. It could ultimately be left to Turkey's military to put a stop to the murderous advance of the fanatic IS.

No case for NATO yet

Up to now, the situation has not been a matter for NATO. With the exception of a few isolated grenade attacks, IS has not attacked Turkish territory. The tomb of Suleyman Shah, which is located on a Turkish exclave inside Syria, also remains intact even though the surrounding territory is under IS control. It remains unclear whether NATO partners would see an attack on the burial place of the grandfather of Osman I, founder of the Ottoman Empire, as an attack on NATO land. But if Turkey itself were to be attacked, Turkey could certainly call on the alliance. NATO's new secretary general, Jens Stoltenberg, expressly said that the alliance would protect "the integrity, the borders of Turkey."

Unspoken sympathy for IS?

But that's not an issue at the moment. NATO's Western allies instead are voicing doubts about Erdogan's motives. US Vice President Joseph Biden has criticized Turkey for supporting jihadists in order to get rid of Syrian President Bashir al-Assad. Biden later apologized, and Turkey resolved to put the incident aside. But Barack Obama's deputy only said what many in the West are thinking: that, to a certain extent, Turkey sympathizes with IS, or at least it did up until recently.

There have been mounting reports that Turkey is releasing jihadists - including those from EU countries - from its prisons in exchange for Turkish IS hostages. And that's undermining the already tense relationship the West has with the Turkish government.

Ankara has high expectations

What is Erdogan's strategy? Clearly he finds himself in a quandary. If he joins ranks with the US in the fight against IS, then he must prepare himself for Islamist attacks on his own soil. But neither does he want Assad or the Kurds to become too strong. For decades now, militant Kurds have been enemy No.1 for Turkey. Erdogan's initial argument - that his hands are tied as long as the Islamists have Turkish hostages ­carries no weight at the moment.

And yet Turkey has named conditions for its participation in the fight against IS: the toppling of President Assad, of "Satan," in the words of Prime Minister Ahmet Davutoglu. And the US-led coalition should establish a buffer zone within Syria. This buffer zone should protect Kurdish civilians - who would then no longer flee across the border into Turkey - as well as provide the Turkish military with a level of security.

In other words, Turkey expects a comprehensive security strategy, including for the time after a victory over IS. But that is asking a lot of a loose coalition which already appears to be overwhelmed with the task it has given itself.

Turkey may have some understandable reasons for its hemming and hawing. But the time for strategic mind games is over now. The Turkish military cannot sit by and watch while IS forces slaughter Kurdish civilians. If it does, the global community will hold Turkey partly responsible.