Let’s say that Assad wins this war with Iran’s backing, what would happen?
The price would be virtually total control of the government in Damascus, even before the revolution Bashar had allowed Iranian influence into Syria much more than his father Hafez ever did. The Iranians aren’t helping Assad out of love. The have hegemonic ambitions to dominate the entire region. It is only with their help that Assad holds on to power, and they will also have the power to remove him if he doesn’t tow their line.
So the war is won. What next? It is clear that Assad would go on a killing spree, slaughtering everyone who he felt was in opposition to him. This would amount to millions of people. There is precedent, his father killed thousands in Hama back in the 80′s when they showed discontent with the regime. The next time will be on a much larger scale and he will have the help of the Iranians in this.
After this, when the clean up is finished, will be when Shia are encouraged to move to Syria and take over certain areas. Someone said that the Shia would be murdered if this were to happen, what you have to remember is that if Assad/Iran win this war there will be such an iron fist of control in the country that the situation before the revolution will seem like a happy time in comparison. The Shia with Iranian backing will in effect have more control in many ways than Assad. He would become no more than a figurehead and he wouldn’t have any choice in the matter. Under these circumstances it will be easy for many Shia to move into Syria.
The impact of all this is that Israel would now have many Shia on its border which effectively means that Tehran will now be next door to them. The balance of power and spheres of influence will have dramatically changed. Why else would Israel have directly armed the Sunni rebels when they were fighting Hezbollah close to its border if it doesn’t feel threatened by having Shia on its Eastern border?