Flat, dry, central Iraq is the Bonneville Salt Flats of insurgency, the War Nerd says, but the hilly north is another story:
No world records set there. In fact, I.S.I.S. seems to be bogging down badly around Kirkuk. To understand why, you need to consider both ethnography and terrain. And in fact, those two things are linked very tightly here, for some grim historical reasons. If you look at an ethnic map of Northern Iraq, you’ll notice that the minority sects and ethnic groups (those two categories tend to run together in the Middle East) are clustered north of the Central Iraqi plain, where the ground rises toward the serious mountains along the Turkish and Iranian borders.
There’s a reason for that, a simple and cruel one: Minority communities that aren’t protected by the hills tend to get wiped out. All over the world, you’ll find groups described as “hill tribes,” and in almost every case, if you go back a few centuries you’ll find that these aren’t “hill tribes” by choice, but defeated tribes who were forced off the plains and into the hills to survive. In places as far apart as Burma and Kurdistan, that pattern holds very clearly.