Pope Benedict XVI

As is tradition, Pope Benedict XVI issues his World Day of Peace Message this New Year's Day. Entitled, "The Human Family, A Community of Peace," the Pontiff focused on the concept of the family as a basis for building peace and justice at all levels of human interaction. One element of his message was his discussion of natural law and its connection to international law.  Benedict submits:

11. A family lives in peace if all its members submit to a common standard: this is what prevents selfish individualism and brings individuals together, fostering their harmonious coexistence and giving direction to their work. This principle, obvious as it is, also holds true for wider communities: from local and national communities to the international community itself. For the sake of peace, a common law is needed, one which would foster true freedom rather than blind caprice, and protect the weak from oppression by the strong. The family of peoples experiences many cases of arbitrary conduct, both within individual States and in the relations of States among themselves. In many situations the weak must bow not to the demands of justice, but to the naked power of those stronger than themselves. It bears repeating: power must always be disciplined by law, and this applies also to relations between sovereign States.

12. The Church has often spoken on the subject of the nature and function of law: the juridic norm, which regulates relationships between individuals, disciplines external conduct and establishes penalties for offenders, has as its criterion the moral norm grounded in nature itself. Human reason is capable of discerning this moral norm, at least in its fundamental requirements, and thus ascending to the creative reason of God which is at the origin of all things. The moral norm must be the rule for decisions of conscience and the guide for all human behaviour. Do juridic norms exist for relationships between the nations which make up the human family? And if they exist, are they operative? The answer is: yes, such norms exist, but to ensure that they are truly operative it is necessary to go back to the natural moral norm as the basis of the juridic norm; otherwise the latter constantly remains at the mercy of a fragile and provisional consensus.

13. Knowledge of the natural moral norm is not inaccessible to those who, in reflecting on themselves and their destiny, strive to understand the inner logic of the deepest inclinations present in their being. Albeit not without hesitation and doubt, they are capable of discovering, at least in its essential lines, this common moral law which, over and above cultural differences, enables human beings to come to a common understanding regarding the most important aspects of good and evil, justice and injustice. It is essential to go back to this fundamental law, committing our finest intellectual energies to this quest, and not letting ourselves be discouraged by mistakes and misunderstandings. Values grounded in the natural law are indeed present, albeit in a fragmentary and not always consistent way, in international accords, in universally recognized forms of authority, in the principles of humanitarian law incorporated in the legislation of individual States or the statutes of international bodies. Mankind is not “lawless”. All the same, there is an urgent need to persevere in dialogue about these issues and to encourage the legislation of individual States to converge towards a recognition of fundamental human rights. The growth of a global juridic culture depends, for that matter, on a constant commitment to strengthen the profound human content of international norms, lest they be reduced to mere procedures, easily subject to manipulation for selfish or ideological reasons.
(emphasis in italics in original;emphasis in bold added)

In short: International law is necessary to keep the power of states in check. International law does exist, but to be effective, international law must be based on natural law. And, Benedict argues, natural law principles are reflected in international legal instruments and in universally recognized international organizations ("universally recognized forms of authority."

At a time in human existence when it is easy to question whether there are any moral principles that are common to  humanity, it is moving to hear a message of hope-- hope that human beings can apprehend, even if only through a glass darkly, such principles-- and hope that such moral principles have indeed managed to find their way, even if imperfectly, into international legal instruments and international organizations.