Pacem in Terris §110

¹¹⁰ There is a common belief that under modern conditions peace cannot be assured except on the basis of an equal balance of armaments and that this factor is the probable cause of this stockpiling of armaments. Thus, if one country increases its military strength, others are immediately roused by a competitive spirit to augment their own supply of armaments. And if one country is equipped with atomic weapons, others consider themselves justified in producing such weapons themselves, equal in destructive force.