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date: 16 January 2018

Diplomacy and International Law

Summary and Keywords

Within the international society, law and diplomacy have always been complementary and interdependent. However, lawyers and diplomats deal with international issues differently, making them rivals to be the primary mode of international interaction. Diplomacy is the art and practice of conducting negotiations between representatives of states; it usually refers to international diplomacy, the conduct of international relations through the mediation of professional diplomats with regard to a full range of topical issues. Nations sometimes resort to international arbitration when faced with a specific question or point of contention in need of resolution. For most of history, there were no official or formal procedures for such proceedings. They were generally accepted to abide by general principles and protocols related to international law and justice. International law is the set of rules generally regarded and accepted as binding in relations between states and between nations. It serves as a framework for the practice of stable and organized international relations. Much of international law is consent-based governance. This means that a state member is not obliged to abide by this type of law, unless it has expressly consented to a particular course of conduct, or entered a diplomatic convention. Interdisciplinary courses, like diplomacy and international law, are designed to help one think critically about diplomatic and international legal issues in real-life contexts, while applying theory to practice and addressing some of the key questions facing the world today.

Keywords: diplomacy, international law, diplomats, lawyers, international arbitration, justice, consent-based governance, interdisciplinary courses


Diplomacy and law are in some ways interdependent and have always been looked on as complementary facets of international society. Yet diplomats and lawyers approach international issues in distinctly different ways, and one frequent theme running through commentary on diplomacy has been that they are competitors to be the primary mode of international interaction, at least in situations short of war. They are the quarrelsome Siamese twins of international relations.

Traditional diplomacy conducted between the official representatives of states, of course, relies on states’ domestic law to provide the protection needed to uphold the principles of diplomatic immunity, and insofar as states make promises to one another in the course of conducting diplomacy, they do so on the assumption that each government rests on an effective system of law at home that will enable it to carry out the obligations that it has taken on. There is therefore a close connection in the traditional view of diplomacy between the conception of states as reasonably reliable maintainers of law within their borders, on the one hand, and states as competent makers and keepers of commitments in negotiations with other states, on the other (Gong 1984). The relationship between diplomacy and international rather than domestic law is more complex.

Similarities and Mutual Reliance

Diplomacy and international law in a sense grew up together, inseparable as manifestations of a complex European international system in which separate centers of political and military power sought autonomy and greater relative capabilities but, because they existed in close conjunction and necessarily transacted much business among themselves, required some means of regulating their relations. Relying on rules of law was one way of meeting this need; practicing diplomatic interchange was another. Both the regulations of law and the bargaining of diplomacy initially encompassed a variety of political or other units, but over time the increasingly dominant “states” both suppressed competitors for influence within the territory over which they declared themselves sovereign and excluded institutions other than their fellow states from the status needed to be either a party at law or a partner in negotiations. The limited character of international law reflected the same loose construction of international society that the experimental nature of diplomacy did; in the sixteenth and seventeenth centuries both were in the process of discarding the presumptions of a civitas maxima founded in Christendom and governed by natural law, and moving toward a positivist conception of a society of secular states observing such rules as they agreed to among themselves and creating and sustaining such diplomatic practices and institutions as they found mutually advantageous.

As Stanley Hoffmann has noted, “The size of the diplomatic field determine[d] the degree of universality of the legal order” (Hoffmann 1965:96). Yet one could say the same thing in reverse. The geographic extent of the international states-system and society as revealed on the map by those states that accepted common modes of diplomacy demarcated the area within which international law operated between juridically equal participants. Just as surely, the domain of the subjects of international law (as opposed to “barbarians” outside, who might be regulated by European international law but who had fewer rights under it and no role in making it) marked the scope of the diplomatic system (Gong 1984). The two activities were both inherent in a setting defined by a diversity of wills moderated by a degree of society among them. Neither was inevitable in the form that it eventually took – past international systems have developed rules other than legal ones, such as purely moral precepts; diplomatic institutions such as resident envoys have not generally been part of those prior systems – but that there would be rules of some kind, and that there would be some means of communicating and managing business among these many wills, does seem to have been required by the kind of world that the European international system turned out to be (Wight 1977; Bull 2002:122–77).

Diplomacy and international law were and are mutually constitutive. Aside from asserted law laid down at a stroke by international judicial institutions, international law is the creation of diplomacy, either through bargaining at a multilateral gathering that results in a proposed convention that would stand as a general principle of law for the entirety or at least the bulk of the members of the states-system; or through discussions among a more limited number of states (perhaps only two) leading to a formal agreement that, if ratified, would have the status of a legal contract among or between them; or as a pattern of behavior that is eventually recognized as customary law (Goldsmith and Posner 2005). On the other hand, international law heavily regulates diplomacy, providing rules under which it is carried on – as in the Vienna Conventions on Diplomatic and Consular Relations of 1961 and 1963, which codify centuries of developing practice on the security of diplomats (Wilson 1967; McClanahan 1989; Frey and Frey 1999; Barker 2006) – and the rules of construction of international agreements, which are borne in mind by diplomats as they negotiate. Every major ministry of foreign affairs has its legal office, the advice of which helps to shape its definition of its diplomatic objectives and the bargaining strategy it employs to obtain them. Insofar as diplomacy represents an attempt to advance some conception of justice, it has been suggested that the path lies through a quasi-judicial analogy – through the idea of judgment by one’s peers, under which states determine their actions toward a fellow state, in part, by their opinion on the justice of its external and internal conduct; they make their opinions known, and attempt to bring the target state to alter its behavior in accordance with those opinions, through the processes of diplomacy (Watson 1983:40–51).

Differences and Perennial Rivalry

Nevertheless, the idea that international law and diplomacy are mutually incompatible has also been a recurrent feature of thinking about international relations. Because the two forms of interaction employ different criteria and different methods, they have frequently been thought to be characterized by contrasting spirits. The literature on “the ideal diplomat” that became a staple of writings on diplomacy from the Renaissance through the seventeenth century at times displayed skepticism about the suitability of lawyers to serve as diplomats. Callières advised against making magistrates diplomatic envoys, describing them as “ordinarily of a less flexible temper, of a more difficult access, and of a less engaging carriage” than are courtiers (Callières 1983:169). By this, he meant that such judicial officers, accustomed to dealing with advocates who were attempting to persuade them in the magistrates’ own courts, tended to be officious and superior in their manner, while what was called for in a minister sent abroad to deal with sovereigns was the ability to please those superior in rank, and to fence skillfully with equals in negotiations. Yet it can also be inferred that Callières believed that suppleness of mind was essential to arriving at the accommodations inherent in diplomacy, while law consisted in the more unyielding application of settled rules.

In the twentieth century, with the emergence of international relations as a separate field of study, self-conscious of its independence from the older discipline of international law, this insistence on the distinction between the bargaining over interests in diplomacy and the assertion of rights in law became more general and more systematically argued. Carving out an autonomous realm of life known as the political, realist thought in particular drew the line distinctly, and not to the advantage of law. Kennan’s detection of the “legalistic-moralistic approach to international problems,” running “like a red skein” through American foreign policy since the turn of the century, left him with little confidence that fixed legal rules, prizing stability, could meet the most pressing need of an anarchical international system, a means of peaceful change. Easing the process of change was “a task for diplomacy” (Kennan 1951:82–9). In this dichotomy between diplomacy’s agile accommodation to transformed realities and law’s unyielding resistance to them, Kennan followed the line of reasoning powerfully stated by both Carr and Morgenthau (Carr 1964:170–223; Morgenthau 2006:283–316, 452–82). Carr in particular asserted that diplomacy was not simply different from but was superior to international law as a way of achieving peaceful change, because the legal method of dealing with conflict was to shut its eyes to the interests at stake and endeavor to apply a supposedly neutral set of legal principles to parties who cared far more about prevailing than they did about complying with legal procedures, while the diplomatic-political method took every interest into account, thereby more fully appreciating the complexity of international disputes and the disadvantages felt by have-not states. Diplomacy, in this telling, was more likely to be the engine of change employed by the dissatisfied, international law to be the bulwark of resistance relied on by the supporters of the status quo.

For their part, students of international law tended to see fewer if any sharp contrasts between diplomacy and international law. Writing early in the twentieth century, Brierly treated them merely as different ways of achieving international cooperation or avoiding international conflict, distinguished mainly by the generality of the principles for settlement arrived at through legal channels and the specificity of the expedients produced through diplomatic ones (Brierly 1928:197–203). Jessup, writing at mid-century, asserted, “There is no […] dichotomy […] between law and diplomacy,” and Dixon, entering the fray late in the century, added that “it should not be thought that any of the various methods of dispute settlement are exclusively ‘judicial’ or ‘diplomatic’” (Jessup 1949:3; Dixon 2000:263). A generalization might hold that those who have approached this subject from a background in diplomacy have tended to draw the distinction more firmly, while those who have treated it from the vantage point of law have more often concentrated on similarities between the two institutions (Reinsch 1922; D’Amato 1972:82–95; Watson 1983:40–51). Nevertheless, the Chichele Professorship of International Law and Diplomacy, which had been established in 1859 – half a century before the setting up of the Wilson Chair of International Politics at the University College of Wales, Aberystwyth – was later shorn of half of its appellation, becoming the Chichele Professorship of Public International Law; the diplomatic yin disappeared, leaving only the legal yang.

In this decades-long debate, Kennan, Morgenthau, and Carr asserted the superiority of diplomacy over international law as a method of dealing with conflict; others, like Reinsch or Leonard Woolf, drew an equally clear line between the two but argued for the greater efficacy of law, and indeed advocated the replacement of diplomacy by law (Wilson 2003). One reason for the entire debate may have been the assumption that the functions of diplomacy are exhausted with dispute resolution, the ground on which diplomacy and law seem to run in parallel as clear alternatives. This view, however, slights the other facets of diplomacy. The ongoing representation of one participant in international society to another, the cultivation of common rather than conflicting interests, the advancement of the wellbeing of one’s citizens and their enterprises abroad – these diplomatic activities are distinguishable from the contests that may be directed either to court or to the negotiating table, and such non-conflictual aspects of diplomacy also proceed within the framework of a developed legal system. In other words, once the full complexity of both law and diplomacy is understood, the perceived necessity of choosing between them begins to seem less clear-cut (Berridge 2002; Bobbit 2002:362).

The Influence of Culture

One suggested unity between diplomacy and law lies in the reliance by both on constitutionalism – on the idea that one can bind the future through agreed-on promises and contracts that embody law and comprise the fruit of diplomacy. This unity may be achieved at the cost of revealing another disparity, however: that between the Western world, which formed this amalgam of thought, and non-Western cultures, which, not resting on the same historical background, have adopted the forms of both law and diplomacy much more readily than their aims and assumptions. Universal formal adherence to the means (through the adoption of diplomatic institutions by all the new members of international society following decolonization, for example) fails to bring with it a comparable belief in the ends, of orderly, peaceful relations among juridically equal political units, guided by a set of norms transcending the interests of the players – ends that, if far from always adhered to in the European system, had been at least approximated to a greater degree than in other historical international systems (Bozeman 1971:ix–xvii; 1994:438–522). Such mistaking form for substance in a world now much more culturally diverse and riven with conflict could account for Bull’s somber view that only “on a narrowly legal view” could it be said that diplomatic institutions were strengthened in the twentieth century, and that the system-wide ratification of the Vienna conventions on diplomatic and consular relations “ushered in a period remarkable for a very high incidence of actual violation of diplomatic immunities” (Bull 2002:177, 156).

Others suggest a similar link between diplomacy and international law as components of a Western-originated system grounded in a Western world-view, but the tie is of a negative character, both of these institutions being tainted by inequality – that is, inequality among political units, since the precepts and procedures of diplomacy and law have been systematically biased in favor of the interests of the dominant powers which originated them, and inequality among the human beings enmeshed in the institutions, especially regarding gender (with the ranks of diplomats being dominated by males, and females relegated to the role of diplomatic spouse, while international law is alleged to display a lack of concern toward abuses of special importance to women) (Der Derian 1991; True 2004:151–62).

It has been argued that the very marriage of the forms of diplomacy with the concepts of law has proved damaging to the conduct of Western diplomacy. In a consideration of diplomacy somewhat reminiscent of Kennan’s critique, Cohen defines a Western, and in particular an American, “low-context” diplomatic negotiating style precisely in its reliance on “legalism” – the assumption that one negotiates by building up a persuasive case founded in logic and precedent in order to arrive at a clear and binding contract. By contrast, he finds that negotiators from “high-context” cultures may display emotion, appeal to status, employ what seems to low-context negotiators to be dissimulation, or calculate solely on the basis of power, but they will not be swayed by the arguments relied on, or the style congenial to, lawyers trying a case or drawing up a contractual agreement. Cohen, however, goes further than Kennan, who described the “moralistic-legalist approach” as an intellectual blind alley down which American diplomacy had been led at a fairly recent point in its history and out of which it could find its way if properly instructed; for Cohen, the “low-context” adoption of legal forms of thought in diplomatic contexts for which they were not suited was a natural outgrowth of fundamental Western cultural practices, carried to their fullest development in the American context and inculcated from childhood in every cultural setting, which would be dauntingly difficult to take up or put off at will (Cohen 1997:135–42).

Diplomacy and Law: Cohabitation or Divorce?

Diplomacy begins with a consciousness of the limitations to one’s power. State and non-state practitioners of diplomacy generally find it impossible (or at least unacceptably costly) simply to take what they want; the existence of other centers of power and authority, possessing their own coercive resources and differing interests, makes proceeding by the sheer imposition of one’s will impossible. Practitioners of diplomacy “have therefore concerned themselves more with expediency, prudence and compromise” than with the handing down of orders (Watson 1992:8). It is in the absence of that very expediency, prudence, and compromise that Kennan finds the “legalistic-moralistic approach” lacking. Still, law, too, assumes that one party to a dispute cannot simply impose its preferred solution, but must instead contend with or cooperate with, and at any rate on some points give way to, an independent will. Both diplomacy and law, in other words, rest on plurality, and on a preference for dealing peacefully rather than forcefully with the constantly varying pattern of conflicting and coinciding interests inherent in any setting of dynamic plurality. Each is willing to employ coercion – law as a punishment, visited upon the guilty for their crimes; diplomacy as an incentive, pressing the recalcitrant toward agreement. Yet the diplomat questions whether the law is flexible enough to withhold retribution from the guilty if mutual advantage demands ignoring legal violations, while the guardian of law fears the demoralizing effect of bargaining with lawbreakers instead of punishing them. Perhaps in a world in which the identities of those who pursue diplomacy are becoming ever more varied, and the consular, representational, and symbolic functions of diplomacy are becoming steadily more important, the similarities, divergences, and symbiotic action of these two forms of international interaction will form the focus of greater academic research and practical action.


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