I've never understood what the real reason we invaded was. I just know it wasn't what we said, or oil.
replies(21):
The us was not going to invade Iran or Saudi Arabia. Fighting militias is difficult.
Having troops there allowed to get the enemy (jihadists) where it was, so troops would serve as a lightning rod.
Iraq was probably the place that was the easiest to invade without to many consequences, where nobody would cry about Saddam going away.
I'm trying to see what strategy it was, of course geopolitics are ugly.