Turkey's decision to call a Nato meeting to discuss the downing of one of its warplanes by Syrian air defences is a measure of the seriousness of the current situation but it also sends a signal that, for now at least, Ankara is looking for a concerted diplomatic response rather than taking military action of its own.
At the very least the downing of the Turkish jet risks a dangerous new twist in the Syrian crisis. Since the start of the unrest, concern at the escalating loss of life inside Syria has been coupled with fears that the violence could move beyond Syria's own borders prompting a broader regional conflagration.
The violence has already seeped into Lebanon but the greater fear was that if the fighting spilled over the border, say into Turkey, or if somehow Hezbollah were to be encouraged by the Syrian regime to lash out at Israel, then this could become an inter-state conflict rather than an insurgency largely confined within the borders of one country.
The episode of the downing of the jet still raises many questions.
- Where exactly was it when it was engaged by Syrian air defences?
- Why had it strayed into Syrian air-space for at least a small part of its flight?
- Why were measures not taken to alert the aircraft's crew of their error before knocking the plane out of the sky?
- Was this just a routine training mission as the Turks say, or was the aircraft seeking to monitor what was going on the ground?
What's clear is that Turkey's concern is shared by other Nato countries. Britain's Foreign Secretary William Hague has expressed his grave concern at the shooting down of the aircraft, which he says, according to the Turkish authorities, had happened "without warning".
Turkey has now determined to take the matter to Nato, calling for an urgent meeting to discuss the situation. Article 4 of the Nato Treaty allows for countries to consult together whenever "the territorial integrity, political independence or security of any of the Parties is threatened".
Turkey might have sought such consultations at earlier stages in this crisis, prompted for example by the flood of refugees across its borders or shelling from Syria into its territory.
For now at least Turkey is not seeking to invoke Article 5 of the Nato treaty which would require countries to offer it practical military assistance. This is what happened after Iraq's invasion of Kuwait when Saddam Hussein threatened Turkey.
Nato warplanes and air defences were, reluctantly it must be said, despatched to bolster its air defences.
Many will wonder if this episode brings the likelihood of direct external military intervention in Syria any closer. The answer is probably no.
The situation on the ground is complex and messy and few countries have much appetite to become involved. In addition the shooting down of the Turkish jet is a reminder of the capabilities of Syria's air defences which are far more extensive than those of Libya, which still required a full-scale US air campaign to destroy.
But what this episode does do is to highlight the escalating dangers as the Syrian crisis continues. As the bloodshed grows and the Assad regime becomes more desperate, so the risk of some untoward event happening which widens the circle of conflict grows accordingly.
Nato's deliberations will raise the pressure on the Syrian regime but it is hard to see them having any practical effect in terms of convincing Syrian President Bashar al-Assad to relinquish power.