I really like Geoffrey Nunberg. I just listened to him read an essay he wrote on the non-apology.
Basically, we know everything there is to know about non-apologies by the time we're seven: you make appropriately contrite noises, and then you go on to point to extenuating circumstances, disclaim any malign intention, and minimize the offense. As in, "Okay, I apologize. But he started it. And I was only kidding. And anyway, it was washable ink."
You can listen the whole thing here.