The history of the Catholic Church’s participation in the formation of international law is as complex as it is fascinating.

After keeping alive a glimmer of the Roman legal order, along with developing its own sophisticated body of canon law, from the Middle Ages onward, the Church and her leading jurists such as Francisco de Vitoria and Francisco Suarez made important contributions to the advent of modern international law in the light of natural law philosophy. With the disintegration of the jus publicum Europeaum in early 20th Century—a phenomenon discussed in great deal by the controversial German jurist Carl Schmitt in his 1950 work The Nomos of the Earth—and the prior fall of the “Papal States” in the 19th, the Church’s role in international law, which was mostly confined to the Holy See’s various concordats with sovereign states intended to protect the rights of the Church, became peripheral at best. That fact has not removed the Church from the international legal arena, however.

Since the advent of the United Nations (UN) in 1945, the Church has, with varying degrees of intensity, acted as a promoter of peaceful transnational cooperation under the rule of law, thus aligning itself—perhaps unwittingly—with the so-called legalist school of international lawyers, i.e., those who keep the faith of the late scholar Louis Henkin that “almost all nations observe almost all principles of international law and almost all of their obligations all of the time.”

Maybe, though, a fresh round of analysis, dubbed by law professors Jack Goldsmith and Eric Posner as “the new international law scholarship,” has offered a more realistic and instrumental account of when and why states rely on, adhere to, and defect from international law. While some of the claims of this new scholarship remain contested, it seems that concepts such as “morality” and “legality” (which have always been vague in the realm of post-World War II international relations) obscure rather than clarify our knowledge of how international law works insofar as they fail to properly account for the significant disparity of state interests that are almost always at play at the transnational level. Moreover, “the new international law scholarship” provides important elucidation on why, for instance, states are often wiling to enter into and comply with complex trade agreements that shift material rewards to powerful national stakeholders while remaining aloof from, say, a hard climate-change treaty that is likely to place a heavy cost burden on “northern” industrialized/post-industrial countries that are among the least likely to feel the immediate effects of global warming. (For reasons of personal sanity, I am leaving to the side the acrimonious debates over whether or not man-made global warming is a real phenomenon.)

The absence of a robust climate-change treaty is just one—and indeed controversial—lacuna in international law. Missing as well are effective human-rights agreements with serious empirical consequences and, much to the chagrin of the Catholic Church’s social magisterium as set forth in Popes Paul VI’s Populorum Progressio and Benedict XVI’s Caritas in Veritate, international institutions and rules that authentically support human development and just economic distribution at the global level. Even if the vision of natural justice envisioned in those and other contemporary papal pronouncements were enshrined in international law, would it matter? Probably not, or at least not until the time comes when actual states with real economic power and global influence believe that they should be bound by right to the teachings of the Catholic Church. Even the most enthusiastic idealist would have to admit that the Church is as far from that reality today as it was during its earliest years under the reign of the Roman Empire.

This splash of cold water should not give rise to despair, however. Even if the Church’s social voice goes unheeded in an increasingly globalized world where the interests of capital are prioritized over labor, culture, and the environment, and the concept of “rights,” specifically “human rights,” has been hijacked by left-leaning academics to advance a number of abominable causes, it does not mean the Church’s witness against these trends is unnecessary.

Accompanying that witness, however, should be a more realistic understanding of the limits of international law for achieving the proper ends of peace, justice, and prosperity. In other words, when the Pope and other competent Church officials speak on matters related to international law, they should always do so with an eye toward faithful Catholics at the domestic level doing what they can to direct their representative governments toward embracing the principles of the Church, which are none other than the principles of Jesus Christ. In times past, before the obfuscation of certain doctrines in the wake of the Second Vatican Council, the Church would have spoken on such matters in the context of the social rights of Christ the King. Regardless of the pluralistic and secularized composition of states today and the global institutions and legal regime they have manufactured, none have the right to carry out policies under the color of law which contradict the universal and intractable law of God.

Of course this is hardly the extent of the Catholic Church’s present difficulties with international law. As noted already, radical left-leaning interests have infected large swathes of international human rights law while international trade and investment law remains hewn to neoliberal economic ideology. The Church itself has come under direct attack from the UN’s Committee on the Rights of the Child in the form of a recent report that ostensibly focused on the sex-abuse crisis only to devolve quickly into a condemnation of Church teaching on abortion, contraception, and homosexuality. And though nothing, thankfully, came of it, the (largely bloodless) International Criminal Court was urged last year to bring sex-abuse charges against Benedict XVI and other Church officials under a distorted application of the doctrine of superior responsibility—a concept that originated in, and only applies to, war crimes cases.

In the grand scheme of things these are minor matters at best, albeit ones that are unintentionally trumped up by Catholic and non-Catholic conservatives who are routinely panicked over the encroachment of international law on state sovereignty. If the Catholic Church is guilty of over-idealizing the efficacy of international law, international law’s critics are just as guilty of overstating their power to trump domestic decisionmaking, particularly in the United States, where constitutional law mandates that any act of Congress supersedes a prior international legal commitment (the “last-in-time rule” or lex posterior derogat priori). Sure, such action may place the U.S. outside of compliance with international law, though the consequences of defection are often slight or illusory. Despite the existence of many multilateral international institutions, those that come affixed with dispute settlement mechanisms typically limit enforcement to bilateral retaliation. For example, if the United States reneged on one of its trade commitments under the World Trade Organization (WTO), only the aggrieved state(s) directly harmed by the defection would, after a long and cumbersome adjudication process, be authorized to take reciprocal retaliatory action against the U.S. The other 150-plus members of the WTO do not enforce collective punishment on scofflaw states.

Given present realities, what should the Catholic Church’s role in international law be moving forward?

After the aforementioned UN report attacking traditional Catholic moral teaching, some have called on the Church—more specifically the Vatican—to remove itself from the organization entirely. What would be the point? The Vatican does not place its freedom in any jeopardy by being afforded the right, under its status as a permanent observer, to participate in the UN’s General Assembly debates and to contribute to proposals, position papers, and draft resolutions and decisions. As for the Holy See’s ratification of such diverse, and inapplicable, treaties as the 1993 Chemical Weapons Convention or the 1997 Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction, the gesture is primarily symbolic and certainly harmless. Besides, isn’t it the responsibility of the Church to set a good example, even if, regrettably, nobody else is paying attention?

The Catholic Church may no longer be a high-level contributor to the development of international law in the postmodern world, but it can still serve as a witness—“the voice of one crying in the wilderness”—concerning international law’s proper intents and purposes. By incorporating a more realistic account of international law into that witness, the Church—and specifically the Sovereign Pontiff—can, hopefully, avoid the pitfalls of tarnishing the credibility of its words with empirically questionable optimism. This refreshed sense of realism could also provide an opportunity for the Church to charitably check the ambitions of legalists within her ranks who may wish to bypass the hard work of evangelizing hearts and minds “on the ground” in order to build Babal-like international legal-institutional structures with the hope of inaugurating an unprecedented epoch of peace and security here on earth.

As the Church’s Slavo-Byzantine Rite reminds the faithful in the litanies recited at services, the only true peace comes from above; what we might achieve for our fellow man materially in the time that remains before the parousia is exponentially less certain and grand, but no less our duty as Catholics.