use whatever force is needed to end the confrontation... if it takes only the force to walk away, then do it... if it only takes a well placed headbutt to the face, then do it - only puss!es call the cops anyways. i don't consider the law when defending myself from aggression, as my first priority is to concern myself with the moment, not something unforeseen in the future... fear of the laws can be a fatal hesitation.