Mater et Magistra §206

²⁰⁶ Yes, both sides speak of justice and the demands of justice, but these words frequently take on different or opposite meanings according to which side uses them. Hence, when rulers of nations appeal to justice and the demands of justice, they not only disagree on terms, but often increase the tension that exists between their States. And so the belief is engendered that if a nation is to assert its rights and pursue its own interests, there is only one way open to it: to have recourse to violence; ignoring the fact that violence is the source of the very greatest evils.