"Russian military presence in Syria"

"Russian military advisers are manning some of Syria's more sophisticated air defenses
– something that would complicate any future US-led intervention...

The advisers have been deployed with new surface-to-air systems and upgrades of old systems,
which Moscow has supplied to the Assad regime since the Syrian revolution broke out 21 months ago.

The depth and complexity of Syria's anti-aircraft defences
mean that any direct western campaign, in support of a no-fly zone
or in the form of punitive air strikes against the leadership,
would be costly, protracted and risky.

The possibility of Russian military casualties in such a campaign
could have unpredictable geopolitical consequences.

...The UN has put the death toll at more than 40,000 as the war continues to escalate.

War is cruelty

The crueler it is 

the sooner it's over

General William Tecumseh Sherman

Employed "scorched earth" tactics against the Confederacy

Turkish officials, who accurately predicted the Syrian regime would use Scud missiles
after several warplanes were shot down by rebels,
also believe President Bashar al-Assad has twice come close to using chemical weapons
including sarin, the nerve gas.

First, after the bombing of the regime's Damascus security headquarters in July,
which killed the president's brother in law
...and then last month, after opposition forces made significant gains.

The Turks and western officials say there are signs Assad sees chemical weapons
as another step in the escalation of force,
rather than a Rubicon-crossing gamble that could end his regime.

I don't care if I follow your rules, if you can cheat, so can I

I won't let you beat me unfairly, I'll beat you unfairly first

Ender Wiggin

Fictional Military Strategist

The US, UK, France and Turkey have warned Syria
that its use of such weapons would trigger military retribution.

But any such a response would be fraught with difficulties.

...The upgrades were supplied by Moscow,
which sees them as a bulwark against western-imposed regime change
and protection of a longstanding investment in Syria.

The country includes Russia's biggest electronic eavesdropping post outside its territory,
...and its toehold on the Mediterranean, a small naval base at Tartus.

...the air defence command, comprises two divisions and an estimated 50,000 troops
– twice the size of Muammar Gaddafi's force
– with thousands of anti-aircraft guns and more than 130 anti-aircraft missile batteries.

...recent Russian deliveries include Buk-M2 and Pantsyr-S1 (known to Nato as SA-22)
mobile missile launch and radar systems.

Reports of the shipment of the modern long-range S-300 have not been confirmed...

It is possible they have been delivered but are not yet operational.

...Sources familiar with the Moscow-Damascus defence relationship
confirmed the presence of Russian air-defence crews inside Syria.

...Such a dense, layered and overlapping air-defence system would require a huge air campaign,
heavily reliant on thousands of precision-guided missiles.

The robust Syrian defences, combined with Damascus's hand-in-glove relationship with Moscow,
and the fragmented nature of the opposition,
help explain why a US-led intervention – predicted as imminent for more than a year
...has so far failed to materialise,
and why there is little appetite for such a move in Washington and most other western capitals,
barring a major, verifiable use of chemical weapons by the Assad regime."

Guardian