Why didn't Bush sr go further into Iraq in 1991? He knew how dangerous Saddam was to his own people.

He wanted to, along with General Norman Schwarzkopf, but an agreement was made with the Saudi's not to invade Iraqi itself as part of the US using Saudi airspace and there military base.

Bush jr had no internationally recognized justification to do that as there was no proof Iraq was a threat to the world.

The justification was the broken UN Resolutions and defiant actions of Saddam towards them. You can spin that anyway you want but the US had the right.

I don't see had you can think that Saddam wasn't a threat to the world. His history says otherwise, do you think he had a change of heart and became a saint and was never again going to hurt anybody? He wanted the US to go down because of the Gulf War and the US led sanctions not to mention he wanted Bush Sr. dead, so Yes, I think he was a threat.