The Syrian government, despite four years of savage fighting and losing control of 80 percent of its territory, is still a going concern. It is believed that the Syrian security forces, which had over 500,000 troops, reservists, paramilitaries and secret police in 2011 now have less than 200,000 armed and organized supporters. About half the losses since 2011 have been from combat but the rest are desertions. In August Assad announced an amnesty for 70,000 Syrian men (with homes in Assad controlled territory) who have refused to show up for mandatory (conscription) military service. Many of these draft dodgers have fled the country but others joined local militias. If nothing else the amnesty enabled the government to update its records.
Despite the many defeats, heavy casualties and even heavier losses from desertion, the Syrian military is still an effective force. This is mainly because the officer corps, or most of it, remained loyal to the Assads. This was particularly true of mid-rank (captains, majors, colonels) officers who are directly responsible for keeping actual combat units (companies, battalions and brigades) intact and operational. A key reason for this loyalty is real estate, or rather a government program that enabled officers to buy apartments or homes in new communities composed mostly of officers families and located near cities. For many officers, who grew up relatively poor in rural areas, getting an education and being selected to be an officer was itself a big deal. But in the 1980s the government began a program that made it easy for an officer to own his own home rather than depending on the cheap, and temporary (for as long as he was in the military) government housing. Owning a home was a big deal to many of these officers, who now had a major financial asset in a place where it was easy to get his kids a good education and exposure to a wider world. The largest of these officer owned housing complexes was outside Damascus. Thus when the war started in 2011 and many officers thought of fleeing the country they had to consider losing their major asset by doing so and the expense of fleeing not to mention the risk of jail if caught deserting in wartime. Enough officers decided to stay to keep the army intact despite four years of heavy fighting and many defeats.
The Assad family that has run the country since the 1960s had given Syria a large organized military force. In 2011 Syrian security forces had over 500,000 personnel (50,000 secret police, 300,000 troops and 100,000 police plus reserves). Most of this force is now gone. Over 70,000 have been killed or badly wounded and over 200,000 have deserted and nearly 100,000 troops are in units that the government is reluctant to send into combat because of loyalty or morale issues. But since 2011 over 200,000 armed men have joined the Assads, mostly as local militia. There’s another 100,000 that are, in effect, garrisons in places like the east (near the coast), Damascus and towns and cities in central Syria that will fight defensively, but will not (or the government will not order them to) move elsewhere.
The army has suffered combat losses and desertions (mostly of Sunnis who were not allowed to rise too high in the officer or NCO ranks) that have not been replaced. Thus the Assads have fewer than 100,000 Syrian troops they can move around to fight the rebels. But these troops still have plenty of armored vehicles, artillery, constant ammo resupply (from Russia) and air support. Russia provides spare parts and tech assistance to keep the aircraft in the air. Russia also brokered a deal whereby Syria gives up its chemical weapons in return for NATO not destroying the Syrian air force and providing the rebels with air support (as in Libya). While Russia does not supply mercenaries like Iran, the Russians have been equally helpful in so many ways. You indeed get by with a little help from your friends.