British and American common law traditionally prohibited abortion only after quickening (when the mother feels fetal movements). But after the U.S. Civil War, states began absolutely prohibiting abortion, based primarily on medical concerns. Then in 1973, U.S. abortion law was dramatically changed by the Supreme Court's decision in Roe v. Wade. Euthanasia means "good or peaceful death"; however, it may also be a form of suicide or killing, where morality depends heavily on motive. Passive euthanasia (a.k.a. "letting die")., includes refusing treatment for oneself and withholding life support for others. Active euthanasia -- a direct, positive act of mercy killing - is forbidden by virtually all ethical codes, though many defend it as a merciful alternative to a lingering, agonizing, fatal illness.