Inter arma enim silent leges - "For among arms, the laws fall silent." A concept that during war, many illegal activities occur. Also taken to mean that in times of war, laws are suppressed, ostensibly for the good of the country.⏎
Ex factis jus oritur - "The law arises from the facts." A principle in international law that one must take facts on the ground into account when considering the legality of certain kinds of questions.⏎
Expressio unius est exclusio alterius - "The express mention of one thing excludes all others." When items are listed, anything not explicitly stated is assumed to not be included.⏎
Ignorantia juris non excusat - "Ignorance of the law is no excuse." Not knowing that one's actions are forbidden by the law is not a defense.⏎