Some of us do. I don't think President Bush cared one way or the other, but certain people close to him wanted boots on the ground in the Middle East, and Iraq was an easy mark. The attacks of September 11 were the excuse they needed, and it was easy to morph Afghanistan into Iraq; we were looking for some bad guy to pay some price. As to the weapons of mass destruction, they were going on faith. The President's advisors told him "Don't worry, they're there. Once we're in, we'll find them". It didn't work out that way, Hussein was bluffing, mostly for Iran.
Not much to do now, and I don't really want to. Criminal prosecution might make some of us feel good, but it can't undo anything. It reminds me of the "birther" movement against Obama; Okay, if it's found out he wasn't actually born in this country, do we erase the last 4 years? Is it a do-over? And President Obama himself has proven he's just another politician.
As an American, the older I get the less partisan I get. They're all full of crap.