Abstract
Based on principles taught constantly by the magisterium and found clearly expressed in the social encyclicals and other documents from Pope Leo XIII to Pope John Paul II, this paper attempts to explain how it is that Catholics should think about what is involved in voting, and especially about how, in certain circumstances, they should exercise this privilege and responsibility. Voting is an act of cooperation in the acts of others, and so must be analyzed on those grounds. By means of a description of the Church’s natural law understanding of the relation between the person, morality, law, and the State, Sections I through VI establish a set of principles concerning the gravity of the goods or evils in which we might cooperate by our vote, so as to enable us to analyze the proportionality involved in the decision. Sections VII and VIII explain the circumstances under which it is legitimate to cooperate in another’s evil acts, which one often does when one votes. Sections IX through XII combine these principles and apply them to various voting situations.