The arms embargo would be a joke - Iraq, Iran or Lebanon would laugh at it. And siding with one side in a civil war, which is what would happen, is stupid. In addition, if Assad goes, all religious minorities will be persecuted - look at the fate of Christians in Iraq, and now in Egypt - ...
Islamic State blows up tower tombs in Syria's Palmyra (Reuters)
from the article: Turkey raises Syria military option; Russia urges caution