23 Among the many factors involved in the fall of oppressive regimes, some deserve special mention. Certainly, the decisive factor which gave rise to the changes was the violation of the rights of workers. It cannot be forgotten that the fundamental crisis of systems claiming to express the rule and indeed the dictatorship of the working class began with the great upheavals which took place in Poland in the name of solidarity. It was the throngs of working people which foreswore the ideology which presumed to speak in their name. On the basis of a hard, lived experience of work and of oppression, it was they who recovered and, in a sense, rediscovered the content and principles of the Church's social doctrine. Also worthy of emphasis is the fact that the fall of this kind of "bloc" or empire was accomplished almost everywhere by means of peaceful protest, using only the weapons of truth and justice. While Marxism held that only by exacerbating social conflicts was it possible to resolve them through violent confrontation, the protests which led to the collapse of Marxism tenaciously insisted on trying every avenue of negotiation, dialogue, and witness to the truth, appealing to the conscience of the adversary and seeking to reawaken in him a sense of shared human dignity. It seemed that the European order resulting from the Second World War and sanctioned by the Yalta Agreements could only be overturned by another war. Instead, it has been overcome by the non-violent commitment of people who, while always refusing to yield to the force of power, succeeded time after time in finding effective ways of bearing witness to the truth. This disarmed the adversary, since violence always needs to justify itself through deceit, and to appear, however falsely, to be defending a right or responding to a threat posed by others. Once again I thank God for having sustained people's hearts amid difficult trials, and I pray that this example will prevail in other places and other circumstances. May people learn to fight for justice without violence, renouncing class struggle in their internal disputes, and war in international ones.
Source: Centesimus Annus (Vatican.va)