Recently, Bishop Marcelo Sanchez Sorondo, a close aide to Pope Francis, and the head of the Pontifical Academy of Social Sciences at the Vatican, invited USA presidential candidate Bernie Sanders to speak at an upcoming conference. The senator from Vermont will speak about creating a "moral economy." POLITICO claims that some of Sander's aids are sweating the visit. Others are fascinated by America's leading Socialist politician is invite by the pope at all. i think it is only natural that the pope and Sanders have ties. I will explain in this article.
The Vatican conference on April 15, which Sanders will attend, is one in which Sanders will address social, economic and environmental issues. Recently, Sanders has said that the Vatican and he can find common ground on many matters. For example, Sanders notes, "'Pope Francis has made clear that we must overcome the globalization of indifference in order to reduce economic inequalities, stop financial corruption and protect the natural environment. That is our challenge in the United States and in the world.'"
Interestingly, as the announcement for the April 15 invitation was announced last week, I had already been reading a book entitled Church, State and Public Justice: Five Views, edited by P.C. Kemeny. In this wonderful book I found an important article on "the Catholic Church's Social Teachings" or CST by Catholic Clarke E. Cochran, who teaches courses in political philosophy, religion and politics, and public policy.
Clarke E. Cochran, in his article entitled "Life on the Border: A Catholic Perspective", outlines the Catholic church's positions and directions provided over the past centuries in the area of CST or Catholic Social Teachings. CST is often defined as "the body of doctrine developed by the Catholic Church on matters of social justice, involving issues of poverty and wealth, economics, social organization and the role of the state."
Cochran emphasizes the concept of subsidiarity at work in CST. He explains, "Subsidiarity counsels that the primary purpose of the state is to assist ('grant help'=subsidium) the primary organs of social life (families, labor unions, businesses and other voluntary associations) to carry out their responsibilities. Secondarily, more comprehensive state institutions (such as the federal government) should provide assistance to states and local government when their responsibilities to the common good from their own resources."  This focus on subsidiarity overlaps with the views held by most democratic Americans and has reflected Sanders' positions as both Mayor of Burlington, Vermont and as Senator in Washington, D.C.
In short, Catholic Social Teachers (or CST) over the past two centuries have greatly supported many of the social democratic concepts developed in the same eras. CST is grounded to a great degree in "Natural Law" theory which is considered the foundation for Catholic moral theology.
"Natural law is a philosophy that certain rights or values are inherent by virtue of human nature and universally cognizable through human reason. Historically, natural law refers to the use of reason to analyze both social and personal human nature to deduce binding rules of moral behavior." Natural Law theory influenced many of America's founding fathers during the Enlightenment, but it had actually been introduced centuries earlier in the writings of Thomas Aquinas. Natural Law has influenced even more greatly both English and American jurisprudence.
Catholic moral theology is a major category of doctrine in the Roman Catholic church, equivalent to a religious ethics. I should add, though, that Catholic moral theology embodies more than CST. "Moral theology encompasses Roman Catholic social teaching, Catholic medical ethics, sexual ethics, and various doctrines on individual moral virtue and moral theory. It can be distinguished as dealing with 'how one is to act,' in contrast to dogmatic theology which proposes 'what one is to believe.'" In short, whereas CST is often something which Bernie Sanders and many socialists, democrats, and most Americans can and do embrace, the areas covered under the whole concept of moral theology are not always common ground, e.g. abortion rights, euthanasia, etc.
On the other hand, I would emphasize that CST itself often embodies manyy important areas of common ground for many socialists, democrats and Americans: the Common Good, Solidarity, Social Justice, and Freedom & Dignity for all.
(1) Common Good is considered the vary reason for government authority under CST. It is granted to the state by God as Cochran writes, "Government has the responsibility to promote community among the variety of social groups and individuals in society."
(2) Under Common Good comes the importance of promoting solidarity. Solidarity has the virtue, according to Cochran, of flowing from "the common good to CST. Solidarity is the 'Yes, I am my brother's keeper' affirmation of the bonds of common humanity. Solidarity is actively caring for justices and the common good, flowing from identifications with the needs of others."
Importantly, solidarity is "an aspect of the Church's attempt to distinguish its social morality from such ideologies as individualism, collectivism and nationalism (and indeed from liberalism and conservatism)." In recent years, Pope Francis has been speaking up around the world about the need for a more moral economy. Sanders likely concurs with this aspect of the Vatican's direction because, as Cochran notes, "Genuine community cannot exist where social and economic conditions exploit some members of the community or place members of the community at too great a distance from each other." This is a common understanding of many socialists world-wide.
Since the instant collapse of Neo-Liberal and Neo-Conservative dominance in American thinking followed by the 2007 Global Banking Crisis, Americans and others across the globe have shown a greater willingness to support both CST and Democratic Social callings in economics and politics.
The movement called Occupy was one example of these movements to fight the growing national and global inequalities brought on by the excesses of neo-liberal and neo-conservative political economic leadership as peoples have suffered under for nearly 5 decades. The rise of the Sanders for President Campaign is a more recent example of the new political and new moral directions in leadership that Americans --and most of the world--desire.
(3) According to Cochran, Social Justice in action or a Just Society is defined as a society "in which the common good is valued and pursued" as much as possible. 
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