It's all in the birthrates

There is an interesting piece by Christopher Caldwell in the FT that picked up a book by a German academic called Heinsohn
He writes that the problem in the Muslim world is youth, not Islam, and that any society where 30% of the pop is 15-29 will start to fight. It's not ideology. When Israel built its wall the palestinians started fighting each other.

"The problem, rather, is that in a youth-bulge society there are not enough positions to provide all these young men with prestige and standing. Envy against older, inheriting brothers is unleashed. So is ambition. Military heroism presents itself as a time-honoured way for a second or third son to wrest a position of respectability from an otherwise indifferent society. Societies with a glut of young men become temperamentally different from "singleton societies" such as Europe's, where the prospect of sending an only child to war is almost unthinkable."

The point about Iran is that it has European birthrates, thanks to the revolution and heroic efforts of literacy in women.
It is a pacific country.