Syrian Kurds' autonomy, if not de facto independence, calls into question neighboring Turkey's policy in the country. By aligning itself with the forces battling the regime of President Bashar al-Assad, it may have inadvertently worsened a security crisis on its southern frontier.
Turkish prime minister Recep Tayyip Erdogan was among the first Middle Eastern leaders to openly declare his support for Syria's rebels. Whereas Turkey had strengthened commercial relations with the country under the guise of its "zero problems with neighbors" policy in the years preceding the revolt, the Arab uprisings forced it to rethink its approach to the region. Rather than seeking to expand its influence by engaging governments, no matter how authoritarian, it quickly changed course after the overthrow of Egypt's Hosni Mubarak, championing the Arab revolutionary cause instead.
The shift is usually explained in sectarian terms, and there is certainly an argument to be made that Sunni Turkey seeks a leadership role in the Sunni world. Syria's uprising is one largely of Sunni Muslims aggrieved by decades of maltreatment under a minority Shia-offshoot Alawite regime.
But the shift might as well have been opportunistic. Turkey recognized that in the long term, the Arab dictators with whom it did business could not survive. If it seeks a leadership role in the region or even to export its model of Muslim democracy, it is better off appealing to the "hearts and minds" of those craving self-determination.
So Erdogan argued that Assad had to go and called on his NATO allies to hasten the dictator's demise. Western powers, however, were—and remain—understandably reluctant to intervene, fearing that they will be pulled into a conflagration where it's less and less clear just who are the good guys, if there are any.
To what extent Turkey has supported the uprising against Assad is unclear. Other foreign backers of the rebellion, notably Saudi Arabia and Qatar, have provided weapons. Turkey has hosted Syrian dissidents and opposition leaders, trained defectors, provided intelligence and probably weapons as well.
As a consequence, Syria's rebels have been able to battle a professional army that is altogether better-equipped, although absent weapons support from the West, they have also turned to—or had little choice but to admit into their midst—radical Islamists who are now among the most effective opposition groups in the war. Turkey finds itself on the side of Al Qaeda-affiliated militants fighting to overthrow a secular regime.
Meanwhile the largest minority in Syria after Assad's Alawite sect, the Kurds, were largely left alone by the regime, enabling them to carve out a polity of their own in the northeast of the country where they soon intend to call elections. Syrian Kurdish militants were trained in Iraqi Kurdistan—from which Turkey buys oil to the chagrin of Nouri al-Maliki Shia government in Baghdad—while Kurdish insurgents in Turkey are able to find refuge across the border. Whether in northern Iraq or northeastern Syria or both, an independent Kurdish state hasn't seemed more imminent in a hundred years.
This is what Turkey's policy has, if not created, then certainly facilitated: the rise of radical Islamism in Syria and a Kurdish separatism within its own borders that is emboldened by the success of Kurds seeking autonomy in Iraq and Syria as well.
It can do little to correct this. Military intervention in northern Syria to suppress Kurdish militancy there could be carried out in the name of aiding the rebellion, but would surely expose Turkey's self-interest and might lead other, Islamist groups to wonder whether they can truly depend on it—even as some are reportedly in battle with the Kurds to preserve Syria's territorial integrity, hoping to establish a religious state in the entire country.
Intervention would also strain relations with Iraq's Kurds, which Turkey has cultivated to put pressure on a Maliki government that Sunni powers in the region see as increasingly an ally of Iran.