Part Three - Life in Christ Section Two: The Ten Commandments - Chapter Two

The Fifth Commandment: You Shall Not Kill

482. What is required for earthly peace?

Earthly peace requires the equal distribution and safeguarding of the goods of persons, free communication among human beings, respect for the dignity of persons and peoples, and the assiduous practice of justice and fraternity.

483. When is it morally permitted to use military force?

The use of military force is morally justified when the following conditions are simultaneously present:

• the suffering inflicted by the aggressor must be lasting, grave and certain;
• all other peaceful means must have been shown to be ineffective;
• there are well founded prospects of success;
• the use of arms, especially given the power of modern weapons of mass destruction, must not produce evils graver than the evil to be eliminated.

484. In danger of war, who has the responsibility for the rigorous evaluation of these conditions?

This responsibility belongs to the prudential judgment of government officials who also have the right to impose on citizens the obligation of national defense. The personal right to conscientious objection makes an exception to this obligation which should then be carried out by another form of service to the human community.

485. In case of war, what does the moral law require?

Even during a war the moral law always remains valid. It requires the humane treatment of noncombatants, wounded soldiers and prisoners of war. Deliberate actions contrary to the law of nations, and the orders that command such actions are crimes, which blind obedience does not excuse. Acts of mass destruction must be condemned and likewise the extermination of peoples or ethnic minorities, which are most grievous sins. One is morally bound to resist the orders that command such acts.