Syria analysis: Can Assad's army withstand growing pressure?
Pressure is building on the Syrian army with a deepening armed uprising and growing defections. Shashank Joshi of the Royal United Services Institute considers how the military, the foundation of Bashar al-Assad's rule, is coping.
Last year, late Libyan leader Muammar Gaddafi ordered his army to forcibly crush a burgeoning protest movement. The eastern part of his army melted away immediately, and over eight months the rest progressively disintegrated to leave a rump of loyal, family-led units.
Thirty years ago to this month, President Hafez al-Assad of Syria ordered his elite forces to level the city of Hama in response to a surging Islamist rebellion. Only one brigade defected. Thomas Friedman - in his book From Beirut to Jerusalem - called this decisive brutality "Hama rules".
Hafez's successor and son, President Bashar al-Assad, is operating under "Homs rules" - neither those of Libya last year, nor Hama a generation ago.
Mr Assad's security forces have been predictably resilient. A regime built around the Alawite sect has stacked its officer corps with co-religionists, fellow tribesmen, and family members.
The 4th Mechanised Division, which recently scrambled to regain control of Damascus' suburbs, is drawn entirely from that sect. So too is the Republican Guard and influential air force intelligence. The Shabiha, an Alawite militia, has also been a useful auxiliary.
In short, Syria's military has been turned into a ruthless confessional militia that is likely to see little future in a post-Assad Syria.
Prediction of collapse
At the same time, no army can withstand stresses of this intensity and duration without suffering problems of morale, integrity and loyalty.
The country's demography means that only Sunni conscripts can fill up the rank-and-file. Although the regime has sought to limit their role in combat, a steady trickle of defections has been unavoidable.
The military opposition's commander Col Riad al-Assad, based in southern Turkey, claims to command 40,000 soldiers in his Free Syrian Army (FSA).
Gen Mustafa al-Sheikh, the highest-ranking defector so far, has estimated the regime's combat readiness as having fallen to "40% for hardware and 32% for personnel".
He argues that there is a grave shortage of manpower, that Sunni officers have fled or been removed, and that large parts of the army are secretly reaching out the FSA to defect.
Gen Sheikh, who has formed his own Higher Revolutionary Council to supersede the FSA, boldly predicts that "the army will collapse during February".
That timeline is highly improbable. It is as much an effort to garner international support and induce further defections, as it is an objective assessment of regime capabilities.
Even if defections are as numerous as the opposition claims, that would still leave the ratio of government-to-rebel forces as more than four-to-one - a margin of superiority exceeding that seen in Libya, supplemented by militias, and with airpower held largely in reserve.
At the same time, President Assad's force long ago passed the point at which they could hope for a final, decisive assault like that of Assad senior at Hama in 1982.
The most important factor is the deepening and widening of the uprising over recent months. Those once wedded to peaceful protest now judge that taking up arms is the only viable option.
One important milestone has been the outbreak of violence this month in Syria's second city, Aleppo. The army is increasingly stretched across fronts that it did not have to worry about last year.
It took days to regain control of suburbs around Damascus, and the town of Zabadani - scarcely 20 miles (32km) north-west of Damascus - was entirely seized by rebels last month.
These growing commitments thin out, and increase the strain on, loyal units. The paradox is that more fighting means more defections, but failing to do so risks conceding territory on which the armed parts of the opposition can regroup and consolidate.
Mr Assad's security forces do retain some advantages.
Libya taught us that rebel control of territory can be tenuous and easily reversible. Indeed, Zabadani is falling back into regime hands.
Moreover, the external support to Damascus outstrips anything that might be flowing to the FSA from Turkey, Saudi Arabia or Qatar.
Russia has already sent tons of ammunition, and this lifeline is expected to remain open.
Gen Qassem Suleimani, commander of the elite Quds Force of Iran's Revolutionary Guard Corps (IRGC), has reportedly served as "chief regime adviser and strategist".
The Guardian reports that he "has taken up a spot in the war room" alongside President Assad and his ruling clique.
There is also diplomatic succour. Regimes can hold together or fall apart based on perceptions.
Russia's angry veto of the modest UN resolution last week sent a powerful signal to those Syrian senior officers of wavering loyalty - Moscow is committed to preserving the regime in some form.
It is rational for officials and groups hitherto sitting on the fence to adjust their loyalty in line with Russia's apparent commitment.
One hope is that even if President Assad is squeezed out, a Yemen-style stage-managed transition keeps the "guts" of the regime in place.
Some vulnerable minorities who see Assad as guarantor of their safety, have compelling reasons to take a gamble on this outcome.
A secret US diplomatic cable from Damascus in 2006 observed "tremendous fear in the Alawite community about retribution if the Sunni majority ever regains power".
Assad's "Homs rules" mean that he has no strategy, only tactics: indiscriminate bombardment of a fragmented opposition, the sharpening of sectarian loyalty to force minority communities to pick sides, and outreach to foreign patrons with a stake in his survival.
It is hard to see how this can do anything but accelerate the militarisation of the opposition, induce greater countervailing help to the rebels from frustrated outsiders, and make it very hard for any pluralistic, democratic settlement to emerge from the wreckage.