Did anybody in the administration or the Pentagon read Tom Friedman's book From Beirut to Jerusalem? It might have given them some clue about what to prepare for when they invaded Iraq. Chapter 4, "Hama Rules," says that "politics in the Middle East is a combination of three different political traditions all operating at the same time."
One is "tribe-like politics." "You had to make sure that if someone violated you in any way -- even the smallest way -- you would not only punish them but punish them in a manner that signaled to all the other families, clans, or tribes around that this is what happens to anyone who tampers with me."
Two is "authoritarianism -- the concentration of power in a single ruler or elite not bound by any constitutional framework." It comes in two flavors: gentle and brutal. The Ottoman Turkish empire was gentle. Two examples of the brutal variety were Hafez Assad of Syria and Saddam Hussein. They survived "not only because they have been brutal (many of their predecessors were just as brutal), but because they have been brutal and smart. They have no friends, only agents and enemies...."
Three is the modern nation-state imposed by Westerners. "What happened in the twentieth century when these new nation-states were created was that in each one a particular tribe-like group either seized power or was ensconced in power by the British and French -- and then tried to dominate all the others."
So, after the invasion of Iraq, one would have thought that someone would have thought it important to suppress tribal rivalries and to assert authority when looting broke out after the fall of Baghdad, for example. By the Middle Eastern standards listed by Friedman, the US looked woefully weak the morning after.