"Turkey may have wisely cloaked its narrow retaliatory options in the language of proportionality"

 Syria can deal 'tit for tat'

[National Interest] "... Turkey’s intelligence-collection capabilities are limited, making target selection difficult and the possibility of air strikes remote. While it could have sent military aircraft to strike Syrian sites, Syria’s capable air defenses complicated the decision. Turkey remembers very well what Syrian air defenses can do to a Turkish fighter jet, and the potential for casualties factored into Turkey’s response.Erdogan and other AKP officials have periodically floated a buffer zone, and in theory, Turkey might have taken advantage of this opportunity to follow through on its oft-repeated threat. Turkey could have argued it needed to invade to push Syrian artillery out of range of Turkish cities and villages. However, deploying ground forces over five civilian deaths would have thrust Turkey even deeper into the Syrian conflict and risked moving too far out in front of its Western and Arab allies. The Erdogan government alone simply could not risk igniting full-scale conflict with Syria, nor could it risk being reined in by the intervention-wary members of NATO.
The Turkish response likely will continue to be tit-for-tat artillery strikes alongside interventionist rhetoric—feinting to help reestablish deterrence. The response fits neatly into a narrative of proportionality and helps assuage domestic frustration with the AKP’s handling of the crisis. Turkey appears intent on managing tensions with Syria and preventing them from dragging Turkey into Syria’s internal conflict. Thus, Turkey may have wisely cloaked its narrow retaliatory options in the language of proportionality.
Though the threat of escalation remains remote and the government seems committed to avoiding war, Turkey still faces an impossible situation: its involvement in the Syrian conflict deepens as its policy options fail to broaden. In part, this reflects forces outside Turkey’s control. Within NATO, Turkey invoked Article IV, and the ambassadors released a joint statement condemning Syrian aggression. However, the alliance has shown little appetite for intervention, and Turkey has refrained from invoking Article V, which would obligate NATO to aid in Turkey’s defense, though not necessarily result in a NATO decision to use military force. The United States, for its part, has refused direct Turkish appeals to support the Syrian conflict militarily.
However, Turkey’s precarious situation stems in part from circumstances of its own making. Caught up in its growing regional stature and increasingly fond of liberal internationalism’s Responsibility to Protect (R2P) doctrine, the AKP government miscalculated deeply in threatening independent action in Syria earlier this year. Such bluster without the considerable tools necessary to carry out its threats constituted a major error in the AKP government’s foreign policy. Turkey’s wisely tempered response to Syria’s brazen downing of the Turkish F-4 merely accentuated the incongruity of its threats and capabilities. Thus, when Syria struck again and killed civilians, Turkey’s unexecuted threats necessitated a response—if only to maintain a shred of credibility.
Ankara’s options were limited from the outset, but breakdowns in relations with regional neighbors have exacerbated the problem.... 
Since the Mavi Marmara incident in which Israeli forces clashed with Turkish civilians—killing nine—aboard a ship attempting to break the Israeli blockade of the Gaza Strip, Turkey has downgraded relations, primarily over Israel’s unwillingness to apologize......  the costs to Turkey have mounted as well. Without access to Israeli military technology, Turkey relies even more heavily on the United States, which contributed minimally in the latest flare-up between Turkey and Syria.
... While military confrontation was always unlikely, Assad has appeared unconcerned with Turkish threats on numerous occasions. Damascus quietly dismissed Turkey’s loud proclamations on possible unilateral intervention—eroding the threat of credible action and undermining Ankara’s overall policy objectives. The shelling, therefore, should not be viewed as the precursor to war but as Turkey enacting the most limited means of reprisal...."