Certainly foreign powers caused a lot of damage to Iran, but nowhere near as much as the Islamic Regime and considering that is what, I hope, we are witnessing the overthrow of. I think that we have cause to be optimistic
What countries backed the mullahs against Iran's secular and left opposition, helping SAVAK kill the opposition?
In 1979 the US was working to prevent anti-anti-Russian forces from coming to power, not the mullahs.
Iranian clergy as an institution starting coming into political power, really, around the time of the Russian-Persian wars, were one of the highest ranking Shia scholars in Iran issues a fatwa supporting the war against Russia.