Pope John XXIII
Pacem in Terris §84
Pacem in Terris: On Establishing Universal Peace in Truth, Justice, Charity, and Liberty
84 And lastly one must bear in mind that, even when it regulates the relations between States, authority must be exercised for the promotion of the common good. That is the primary reason for its existence.
Source: Pacem in Terris (Vatican.va)