Traditional medical ethics and law draw a sharp distinction between allowing a patient to die and helping her die. Withholding or withdrawing life sustaining treatment, such as by abating technological nutrition, hydration or respiration, will cause death as surely as a lethal injection. The former, however, is a constitutional right for a competent or once-competent patient, while the latter poses a risk of serious criminal or civil liability for the physician, even if the patient requests it.