Pope John XXIII
Pacem in Terris §54
Attainment of the Common Good Is the Purpose of the Public Authority
54 The attainment of the common good is the sole reason for the existence of civil authorities. In working for the common good, therefore, the authorities must obviously respect its nature, and at the same time adjust their legislation to meet the requirements of the given situation .(37)
Source: Pacem in Terris (Vatican.va)