David Hare Sees How War Plays on World Stage   LONDON -- "Stuff happens!" Donald Rumsfeld once exclaimed in response to a reporter's question about the looting of Baghdad after the U.S. invasion of Iraq in 2003. "Freedom's untidy," he went on to explain, "and free people are free to make mistakes and commit crimes and do bad things. They're also free to love their lives and do wonderful things, and that's what's going to happen here."