Summary
The impact of the stunning seizure of large tracts of northern Iraq by the extremist Islamic State of Iraq and Greater Syria (ISIS) last week could have significant consequences for the Syrian regime's ability to hold onto power.
Already the reverberations of ISIS' dramatic advance toward Baghdad is being felt in Syria, with Syrian rebels in the Qalamoun area taking advantage of the return home of Iraqi Shiite paramilitary forces to stage a counterattack in Rankous.
It is estimated that there are around 5,000 Hezbollah fighters in Syria at any one time and the party represents the main offensive force in launching operations backed by Syrian airpower and artillery to recapture territory. There were an estimated 20,000 to 30,000 Iraqi Shiite fighters serving in Syria before the ISIS offensive in northern Iraq.
The main role of the Iraqi Shiites and the NDF is to garrison captured territory, allowing Hezbollah and the Syrian army to mount fresh offensives elsewhere.
If a significant number of Iraqi Shiites are redeployed from Syria to Iraq, then it is likely that rebel groups will take advantage of the weakened loyalist forces to try and roll back some of the regime's territorial gains.
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