Why Did We Invade Iraq?

We had to know that by installing democracy, we would enable the rise of a Shia government, and thus expand the influence of Iran. I get it. Saddam got off the dollar. Something had to be done. But he was our guy. Maliki? I don’t think he’s our guy. We knew there were no WMDs. We didn’t get exclusive oil rights. We certainly didn’t save or increase the quality of lives. The only thing I can figure is that maybe we WANT Iranian influence to expand, because enemies galvanize dictatorships. But I am open to a better explanation.