this is not a war by an outside force like the Serbs of ethnic cleansing against a neighbor, but rather it is a civil war. The Alawis, Christians and secular-minded Sunnis in Syria are afraid of the rebel forces and either support or are neutral toward the Syrian government; together they may well come to half the country. That isn’t exactly a mandate for outside intervention.
According to Juan Cole (who IMO has a pretty good feel for the Middle East), Assad has the backing of ~50% of the population.
http://www.juancole.com/2013/08/bombing-unlikely-effective.h...
this is not a war by an outside force like the Serbs of ethnic cleansing against a neighbor, but rather it is a civil war. The Alawis, Christians and secular-minded Sunnis in Syria are afraid of the rebel forces and either support or are neutral toward the Syrian government; together they may well come to half the country. That isn’t exactly a mandate for outside intervention.
I don't think its just Assad driving this.