The Donner Party would be off the hook in Idaho
A law (still currently on the books) in Idaho provides for an affirmative defense against cannibalism under certain conditions.
CRIMES AND PUNISHMENTS
18-5003. CANNIBALISM DEFINED -- PUNISHMENT. (1) Any person who wilfully ingests the flesh or blood of a human being is guilty of cannibalism.
(2) It shall be an affirmative defense to a violation of the provisions of this section that the action was taken under extreme life-threatening conditions as the only apparent means of survival.
(3) Cannibalism is punishable by imprisonment in the state prison not exceeding fourteen (14) years.
[18-5003, added 1990, ch. 210, sec. 2, p. 468.]