Pacem in Terris §93

⁹³ There may be, and sometimes is, a clash of interests among States, each striving for its own development. When differences of this sort arise, they must be settled in a truly human way, not by armed force nor by deceit or trickery. There must be a mutual assessment of the arguments and feelings on both sides, a mature and objective investigation of the situation, and an equitable reconciliation of opposing views.