I've noted that the Russia-Turkey tension over Syria has raised my pucker factor considerably.
As of the moment, Turkey denies having "security forces" inside Syria.
Although it may depend on how the Turks define that term. If Turkey plans to send troops into Syria, I'd expect special forces-type forces (perhaps intelligence agency people for definition purposes) to be sent in first.
Have no doubt that Turkey is leaning forward on the question of sending troops into Syria:
Turkey will not allow the northern Syrian town of Azaz to fall into the hands of a Kurdish militia and its fighters will face the "harshest reaction" if they approach it again, Prime Minister Ahmet Davutoglu said on Monday.
A major offensive supported by Russian bombing and Iranian-backed Shi'ite militias has brought the Syrian army to within 25 km (15 miles) of the Turkish border.
So these advancing forces are within artillery range of Turkish guns inside Turkey:
"Starting from February 13, Turkish artillery concentrated in border areas is carrying out massive strikes on Syrian towns recently freed from terrorists by regime forces and Kurdish militia," a statement by the Russian foreign ministry said.
While drones or aircraft could be spotting for the artillery, so could forward observers on the ground.
The Turks are not happy with the Iranians and and their Iraqi foreign legion fighting there. And they really aren't happy about the Russian support for the Kurdish offensive.
On the other hand, I imagine America and NATO officials are trying to restrain the Turks to avoid making this a Russia-NATO fight.
As I've said, Russia is outgunned overall. But Russia can concentrate power against weakness in the most eastern portions of NATO.
And Russia has lots of nukes. So there is that.
Oh, and here's another lovely bit of potential friction between Turkey and Russia:
Two years after Russia seized Crimea from Ukraine, President Vladimir Putin touts the move as a historic achievement, looking on with a satisfied smile from countless billboards across the peninsula. However, overwhelming opposition from the Muslim Tatar ethnic minority puts a crack in this picture of unanimous support, as evidenced in interviews with more than two dozen Tatars across Crimea. And the resistance appears to be growing.
Turkey isn't mentioned at all. But the Turks could try to exploit this budding resistance by Moslem residents of Crimea who have no love for the Russians. Who are the Russians, who claim special privilege to "protect" ethnic Russians (or just those who speak Russian) everywhere, to complain about this urge to protect?
So a Russian-Turkish war over Syria would quickly spread to the sea from the eastern Mediterranean up to the Black Sea, and into Europe in Crimea where another conflict simmers between Ukraine and Russia.
UPDATE: If fighting between Turkish and Russian forces breaks out, NATO ships will be right in the middle of it:
With more than a million migrants having reached Europe in the last year and many more on the way, NATO stepped into the crisis for the first time on Thursday, saying it would deploy ships to the Aegean Sea in an attempt to stop smugglers. ...
Officials said three NATO vessels, from Canada, Germany and Turkey, were being deployed to the Aegean Sea under the command of Jörg Klein, a German rear admiral.
I'm sure the Russians would leave these NATO--including one Turkish vessel--warships alone, knowing they are on a migrant mission and not a threat to Russia's Mediterranean squadron, right?
UPDATE: Why the rise of Syria's Kurds is such a sore spot with Turkey:
The civil war is escalating in southeastern Turkey, with the government pledging to stamp out militant Kurds. Young Kurds, who used to hurl stones and Molotov cocktails, are now fighting on the front lines in several cities.
Turkey wouldn't be the first country to see a foreign threat as a convenient way to settle a domestic division. Much could be done in relative obscurity against internal Kurds while a high-profile conflict with Russia rages.