Interesting article on the My Lai massacre. The court martial found that the task force commander had wrongly made no clear distinction between combatants and non-combatants and this kept the blame from rising too far up the chain of command. The article's author obtained a copy of the top-level directive which governed this type of action. It basically said that if an area was temporarily controlled by the Viet Cong then you should be careful not to kill civilians so as to avoid embittering the population. In areas sympathetic to the Viet Cong - "accepted VC bases" - there are no civilians so they could "kill anything that moved".