As I wrote in my early 2003 American Conservative article on why Iraqi social structures were likely to undermine America's goal of nation-building in Iraq, "Cousin Marriage Conundrum" (which Steven Pinker selected for his anthology The Best American Science and Nature Writing, 2004 anthology), about half of the married couples of Iraq are first or second cousins.
Reading Daniel Yergin's history of the oil industry, The Prize, I discovered a great example of the logic behind this.
Imagine you are the dictator of an oil-rich country. Who is the most likely person to overthrow you?
Your Minister of Defense, right?
So, you could appoint your own first cousin as Minister. He'd be more loyal to you than some stranger would.
Yet, Shakespeare's history plays about struggles for the English crown have been characterized as the War of the Cousins.
Or, you could appoint your own son-in-law. He'd be more loyal than some stranger would.
Yet, King James II of England was overthrown in 1688 by his son-in-law William of Orange.
But, if you were Saddam Hussein, you could appoint your own first cousin who is also your brother-in-law!
The new Iraqi regime -- particularly the party, military, and security services -- was dominated by Tikritis, many of them related in some way to Hussein. So obvious was their grip that in the mid-1970s the government banned the use of names that indicated clan, tribe, or locality of origin. At the top sat members of Hussein's Talfah family and two other immediately related families, the only people he could trust -- to the degree that he could trust anybody. He has already married his cousin, the daughter of his uncle Kahyr Allah Talfa. Now Adnan Khayr Ala Talfah -- son of his uncle, brother of his wife, his own cousin -- was Minister of Defense (a post he held until his death in a helicopter crash in 1989). Hussein Kamil Al-Majid, who happened to be both Hussein's cousin and son-in-law, became chief weapons buyer, and responsible for the development of nuclear and chemical weapons and missiles. And the influence of [uncle and father-in-law] Khayr Allah Talfah continued to be felt. In 1981, the government printing house distributed a pamphlet by Talfah. Its title gave some idea of the thrust of his political thought: Three Whom God Should Not Have Invented: Persians, Jews, and Flies.