The Russians are right about the terrorist opposition being funded and supported by external forces (NATO, Qatar, Saudi Arabia, Turkey). If that support can be cut off, then the violence will end very quickly.

what we have here is a difference of opinion.  Some people think that country belongs to all of the people who live there and that the state is required to treat them equally.  Other people believe that a country belongs to a dominant group and that the ruling class is required to manage the people as a herd of wild cattle grazing on the land.

People of the first group do not consider a country valid if the herd is unhappy.  People of the second group see any attempt to influence the herd as destabilaztion.

Historically, the world has been dominated by the second group since the pharohs.  However, that started changing when the americans broke from England and drafted a successful ecnomic model for free range cattle.  It capitalized upon happy cows for increased productivity and creativity.  This led to a wave of revolutions and wars.  Some, like the French, ended successfully after a bloody transformation.  Some, like the English, adapted peacefully. Others, like the Russian, were hijaaked and turned back towards the second group.  Now, as a person scans the international scene, the first group outnumbers the second group by about 170 to 30. 

Most of the mideast is in the second group.  Arab spring is actually a very angry group of cattle.  They are stampeding and demanding to be part of the first group.  The stampede is spreading to every country where the cattle are not well fed and pampered.  Assad is yelling "wolf" and shooting any cattle that stray.  It only made the stampede worse. 

Nobody, not even from group two, actually believes that they are wolves.  Assad is still trying to regain the herd by slaughtering any of them who do not obey.  The real question is "at what point should the free range cattle of the world join with those of Syria?"

As regards Iran and Russia.  Make no mistake.  They are group two.  Their bigest fear is that their own cattle may someday demand happiness and freedom.

(correction): Another foolish try as it was done in Yugoslavia, a NATO “peace keeping forces” who encouraged the hostilities/conflict s and not the ceasefire.