Mater et Magistra §203

²⁰³ Yet although individuals and nations are becoming more and more convinced of this twofold necessity, it would seem that men in general, and particularly those with high responsibility in public life, are showing themselves quite incapable of achieving it. The root of such inability is not to be sought in scientific, technical or economic reasons, but in the absense of mutual trust. Men, and consequently States, are in mortal fear of each other. Each fears that the other harbors plans of conquest and is only waiting for a favorable moment to put these plans into effect. Hence each organizes its own defense and builds up munitions of war as a deterrent against the would-be aggressor.