Evangelium Vitae §72

⁷² The doctrine on the necessary conformity of civil law with the moral law is in continuity with the whole tradition of the Church. This is clear once more from John XXIII's Encyclical: "Authority is a postulate of the moral order and derives from God. Consequently, laws and decrees enacted in contravention of the moral order, and hence of the divine will, can have no binding force in conscience...; indeed, the passing of such laws undermines the very nature of authority and results in shameful abuse". This is the clear teaching of Saint Thomas Aquinas, who writes that "human law is law inasmuch as it is in conformity with right reason and thus derives from the eternal law. But when a law is contrary to reason, it is called an unjust law; but in this case it ceases to be a law and becomes instead an act of violence". And again: "Every law made by man can be called a law insofar as it derives from the natural law. But if it is somehow opposed to the natural law, then it is not really a law but rather a corruption of the law". Now the first and most immediate application of this teaching concerns a human law which disregards the fundamental right and source of all other rights which is the right to life, a right belonging to every individual. Consequently, laws which legitimize the direct killing of innocent human beings through abortion or euthanasia are in complete opposition to the inviolable right to life proper to every individual; they thus deny the equality of everyone before the law. It might be objected that such is not the case in euthanasia, when it is requested with full awareness by the person involved. But any State which made such a request legitimate and authorized it to be carried out would be legalizing a case of suicide-murder, contrary to the fundamental principles of absolute respect for life and of the protection of every innocent life. In this way the State contributes to lessening respect for life and opens the door to ways of acting which are destructive of trust in relations between people. Laws which authorize and promote abortion and euthanasia are therefore radically opposed not only to the good of the individual but also to the common good; as such they are completely lacking in authentic juridical validity. Disregard for the right to life, precisely because it leads to the killing of the person whom society exists to serve, is what most directly conflicts with the possibility of achieving the common good. Consequently, a civil law authorizing abortion or euthanasia ceases by that very fact to be a true, morally binding civil law.