The most dangerous thing facing any nation is whether their own leadership is compromised.
If the Iranian leadership isn't compromised, the americans could kill ten million iranians and they wouldn't be able to topple iran. But if your leadership is heavily infiltrated, then its really about creating the domestic conditions which opens the doors for the "agents" to set the agenda in motion.
Its like the enemy within your own fort, its only once the enemy is at the walls that he can do his damage and open the doors from within.