Success depends on military intervention.  There is no reasonable chance of success for the opposition movement absent substantial military re-enforcement by the West.  The Syrian government is uniquely placed for several reasons to be able to quell any opposition movement and to rule by fear and force for an indefinite amount of time. Bashar al-Assad’s legitimacy is and never has been based on any type of democratic mandate or popular support. He rules based on control and, as such, has built up many institutions to entrench this capacity to control the Syrian public over the years. Oil revenues are high and Assad has very deep monetary reserves that allow him to buy loyalty from his military and equip himself beyond the capacity of any domestic opposition group could feasibly do.  Due to these two factors, the only way that Assad will fall is by force and by force that is far greater than can be attained without the support of the West. Therefore, for the humanitarian situation to be solved, the West must invade Syria.