Today we go back to year 1963 and look at a ground breaking papal encyclical Pacem in terris ( 'Peace on Earth') issued by Pope John XXIII. Published months after the Cuban Missile Crisis, which had brought the world to the brink of nuclear war, some commentators called this encyclical the popes ‘Last will and testament’ as he would die less that two months later. It had an unprecedented impact, at time of geopolitical insecurity. It lead to the Pope being named Time Magazine 'man of the year', the UN leading international congresses discussing its contents.
Pacem in terris was the first encyclical that a pope had addressed to "all men of good will", rather than only to Catholics. In its seven-paragraph introduction, it spells out clearly the natural law methodology that underpins the encyclical. In an attempt to make the encyclical reach a wider audience then normal, the natural law approach meant that non-Christians and non-believers could understand and respond to the document. It was not based on specifically Christian theological sources. The thinking was that all humanity could discern this order and law in human nature and in conscience. This also marked a shift in papal teaching away from classical scholastic categories of natural law to an approach based on ‘the signs of the times’ (a phrase that had become popular in the second Vatican council). Many encyclicals assumed and built on the theological categories of redemption, Jesus Christ, and grace, but as pacem in terries is addressed to a wider audience it relied on natural law because as Mary Ann Glendon, Professor of Law at Harvard Law School, said that "The Pope was insisting that the responsibility for setting conditions for peace does not just belong to the great and powerful of the world—it belongs to each and every one of us." F. Russell Hittinger, a Professor of Law at the University of Tulsa, described the encyclical "as a kind of magna carta of the Catholic Church's position on human rights and natural law". The Pope emphasizes the importance of respect for human rights as an essential consequence of the Christian understanding of humankind.
Reflecting its importance and popularity, Pacem in Terris was also deposited at the UN archives and two years later, was the subject of a conference at the United Nations attended by over 2,000 statespersons and scholars. It was the first papal encyclical published in its entirety in the New York Times. He was voted Time Magazines person of the year 1962. Pope John XXIII was reacting to a perilous geopolitical atmosphere, just months after the 1962 Cuban Missile Crisis, during which the Vatican served as an intermediary between the White House and the Kremlin. Pacem in Terris also reflected the Pope's experience of 1960 in trying to resolve difficulties arising out the four-power occupation of Berlin, it was only two years after the erection of the Berlin Wall. In international affairs, the Pope had already engaged in dialogue with the Communist countries of Eastern Europe, working to reconcile with the Russian Orthodox Church to settle tensions between the local churches. He had begun dialogue with Soviet leaders in order to seek conditions in which Eastern Catholics could find relief from persecution. Surprisingly the Second Vatican Council did not mention Communism, in what some have called a secret agreement between the Holy See and the Soviet Union. In Pacem in Terris, John XXIII also sought to prevent nuclear war and tried to improve relations between the Soviet Union and the United States.
The encyclical as a whole can be understood as an extended reflection on the moral order. The document is divided into four sections. The first section establishes the relationship between individuals and humankind, focusing on the issues of human rights of the collective and the moral duties of the person. Mentioning the rights of women, nuclear non-proliferation, and the United Nations, all of which it endorsed. The second section addresses the relationship between man and state, focusing mainly on the collective authority of the latter. The third section establishes the need for equality amongst nations and the need for the state to be subject to rights and duties that the individual must abide by. The final section presents the need for greater relations between nations, thus resulting in the possibility that collective states assist other states. The encyclical ends with the urging of Catholics to assist non-Christians and non-Catholics in political and social aspects. Heavily influenced by Saint Augustine's The City of God and Thomas Aquinas' view of Eternal Law it radically affected Catholic social teaching not only on war and peace, but on church-state relations, women's rights, religious freedom, international relations and other major issues.