Populorum Progressio §60

⁶⁰ As a matter of fact, the highly developed nations have already come to realize this. At times they take appropriate measures to restore balance to their own economy, a balance which is frequently upset by competition when left to itself. Thus it happens that these nations often support their agriculture at the price of sacrifices imposed on economically more favored sectors. Similarly, to maintain the commercial relations which are developing among themselves, especially within a common market, the financial, fiscal and social policy of these nations tries to restore comparable opportunities to competing industries which are not equally prospering.