The evidence is conclusive. Iran is a mono-ethnic nation state stubbornly intent on preserving its racial, cultural and religious heritage, something to which no nation but Israel is entitled to do.
Then there's the oil. One hundred and fifty billion barrels, or $15 trillion-worth at the wellhead. That's far too much cash for such a populous country in such a geostrategically important part of the world to invest in in its own development.
What's more, they have to restore control of the oil fields to the Anglo-Iranian Oil Co. (aka BP) and Exxon.