In 1943 the U.S. War Department produced a book offering guidelines for our soldiers fighting in Iraq. It contained advice such as this:
The tall man in the flowing robe you are going to see soon, with the whiskers and the long hair, is a first-class fighting man, highly skilled in guerilla warfare. Few fighters in any country, in fact, excell him in that kind of situation. If he is your friend, he can be a staunch and valuable ally. If he should happen to be your enemy — look out!
There are also political differences in Iraq that have puzzled diplomats and statesmen. You won’t help matters any by getting mixed up in them.
A pdf version has been posted here.