The conflict in Syria tends to be seen as one between a disparate, fragmented rebellion and a centralized dictatorial regime.
This characterization of the rebellion is correct. The view of the Assad regime as a centralized, monolithic unit, however, is no longer accurate.
These forces are all committed to keeping Bashar Assad in his seat as president of Syria – whatever that means today. But the evidence suggests that he does not control or command all of them, and indeed may not be setting the strategy for the war against the rebels.The "regime side" in Syria, too, has become an alliance of various forces.
How did this situation arise? The Assad regime was, throughout its existence, a quintessentially centralized affair – an East Germany on the Mediterranean. To be sure, myriad networks of patronage existed within its structures, but the structures themselves were solid.
The problem for the Assad government in its long fight with the insurgency is manpower.
The dictator vastly outclasses the forces arrayed against him in terms of hardware; what he lacks is men willing to engage on his behalf. This is because of the sectarian nature of his regime, and its consequent narrow base of support.
On paper, of course, Assad commands a vast force. The Syrian Arab Army notionally consists of 220,000 troops in 12 divisions, plus an additional 280,000 reserves. But in practice, the majority of this force consists of Sunni conscripts, and is therefore unusable.
This chronic shortage of manpower has defined regime strategy throughout the war. Assad ceded around 60 percent of the country to the rebels and the Kurds in mid- 2012, because he lacked sufficient available forces to control it.
Necessity forced him to reduce the area under to his control to a size that he was able to manage with the manpower available to him.
Iran is committed to Assad's survival.
He is Tehran's main Arab ally, and a vital land link between Shi'ite Iraq and Hezbollah-controlled Lebanon.
Iran is largely – though not solely – responsible for the mobilization of external and internal forces on behalf of Assad, which is intended to solve the shortage of available fighting men.
The fighters were brought in from a variety of places.
Firstly, the Iranians have committed men of their own. The Islamic Revolutionary Guards Corps maintains an operational base in Damascus.
Qods Force commander Qassem Suleimani visits the country regularly to command and coordinate operations.
In June, the British Independent on Sunday newspaper reported that 4,000 IRGC personnel were on their way to Syria.
A former Lebanese intelligence officer, speaking to this reporter in August, said he estimated that around 5,000 Iranian personnel are on Syrian soil.
A Syrian rebel officer, Lt. Bilal Khabir, speaking with this reporter, said Iranian personnel were present among his unit in the earliest days of the uprising, when they were sent to quell demonstrations in Deraa province.
Secondly, Hezbollah fighters are involved. They led the regime's retaking of the strategically vital town of Qusair in August of this year. Today, the terrorist militia remains in control of the town. Lebanese media sources estimate that up to 10,000 Hezbollah fighters are present in Syria at any given time.
They are deployed not only in Qusair and Homs, areas of combat close to the Lebanese border; rather, evidence has also emerged of movement fighters in Damascus and the Aleppo area.
In addition, Iran has sought to improve the combat capabilities of the 50,000-60,000 mainly Alawite irregular fighters who have fought on Assad's behalf since the conflict began.
These Shabiha ("ghost") forces have been offered training by the IRGC and Hezbollah and have been organized under the banner of the "National Defense Forces." They are now playing a vital auxiliary role in a number of areas.
Iraqi Shi'ite militias such as the Ahl al-Haq and Kata'ib Hezbollah organizations have also deployed fighters in Syria, mainly in the Damascus area.
Lastly, independent pro-government paramilitary brigades are still operating. These include both Syrian Shi'ite Islamist units, such as the Abu al-Fadl al-Abbas Brigades, and non-Islamist units operating under a variety of ethnic or ideological labels, or no label at all.
These can include some frankly bizarre elements. For example, Aymenn al-Tamimi, a researcher of Syrian paramilitary groupings on both sides, this week published a profile of an organization calling itself the Syrian Resistance, led by a superannuated Turkish Alawite leftist by the name of Mihrac Ural.
This group, which operates in the Latakia area, makes use of antique Marxist symbolism, mixed with Alawite sectarianism.
Moreover, elements among Assad's Shabiha militia in the regime enclave on Syria's western coast are now engaged not only in warfare, but also in significant economic activity of their own, independent of official channels.
Of course, the presence of this array of paramilitary groups should not obscure the extent to which Assad may still call on formidable forces of his own. The Fourth Armored Division, his Special Forces and the Republican Guard all remain available to him, as well as parts of the army, the intelligence services and the air force.
But a large and disparate gathering of forces have been brought in to plug the gap in manpower that is the main strategic threat facing the dictator.
Assad desperately needs these forces, though he did not establish them and he is not paying for them.
So it may be cautiously deduced that he is unlikely to be controlling them.
There remains a major difference between the regional Shi'ite effort to back Assad, and the Sunni help afforded the rebels. The latter is a tangled web of differing and often hostile interests – Saudi Arabia, Qatar, Turkey, private Gulf funders, the Muslim Brotherhood.
The former, however, is coordinated by a single external force – namely Iran.
This does not mean that all the elements involved are merely puppets of the Iranians. But it almost certainly does mean that they are not taking orders from the Syrian despot.
In this way, the Assad regime has become merely one element in a combined effort of Iran-aligned paramilitary forces to maintain their area of control within Syria.