Turkey shouldn't sit on its border with tanks expecting an explicit plan against the ISIL that would lead to Damascus, but the Turks should imply that inevitably any and all real fighting against the ISIL must lead to the Syrian source of instability in the Levant and beyond.
Bashar al-Assad's creation of strife and warfare and of crimes against humanity committed by Syrian forces that gassed hundreds of children to death in attacks on civilians that have forced three million Syrians from their homes, are the driving forces of the ISIL. The known atrocities of Assad's forces has swelled the ranks of the ISIL and in spite of air strikes from Iraq to Syrian, the ISIL cannot be defeated while Bashar al-Assad sits in Syria.
So while Turkey's apprehension to engage the ISIL could be taken but for so long, the Turks, who have longed for an opportunity to establish a leadership role in the region, could seize upon the ground defense and protection of Kobani as a step along the road to Damascus. Time is running out on Turkey to act because old wounds involving the Kurdish Turks could come to bear adversely, thus time is of the essence for Turkey to act so that it does not become entangle in domestic and internal defenses instead of traversing the sands to Damascus.