True. If the USA had had the sense to leave Iran alone WAY back in the 1950's, instead of toppling their elected government in a CIA-planned coup, then the authoritarian religious rule of the Ayatollahs would never have come about in the first place. It is indeed a symbiotic relationship, as you suggest.

As for Ahmadinejad, he's not the ruler of Iran. He's the president. The president is not the ruler or the top person in Iran, he's an underling. The ruler is the Ayatollah. What Ahmadinejad is, is he's a perfect poster boy for the USA's anti-Iranian propaganda...worth his weight in gold to Washington at the moment. Without him there, they'd have to find another boogeyman...and they would. There's always another one. Just like on TV, the story has to have its official "bad guy" to keep the public interested. It helps a lot if he has facial hair, but it's not an absolute necessity.