Benjamin Joseph Salmon was an American Christian pacifist, Roman Catholic, conscientious objector and outspoken critic of just war theory. Salmon believed no war could be morally justified.

A conscientious objector is an "individual who has claimed the right to refuse to perform military service" on the grounds of freedom of conscience or religion. The term has also been extended to objecting to working for the military–industrial complex due to a crisis of conscience. In some countries, conscientious objectors are assigned to an alternative civilian service as a substitute for conscription or military service.