This might be hard to understand for us, but I am sure there are Sunni civilians who would rather be under ISIS rule that Assad or Iraki rules. Isis found a fertile ground because Sunnis area were oppressed or neglected by their central government.<p>At any sign of serious ground military actions, all that ISIS fighter have to do is to hide in their civilian population. And that will be Fallujah all over again.<p>This is the reason why currently no one consider seriously to send ground troops.