II. The contribution of the UN collective security system to the shaping of the New World Order

In the periodisation Hathaway and Shapiro deploy, the emphasis placed on 1928 – the Peace Pact – has the effect of diminishing the importance attached to 1919 – the Covenant of the League of Nations – and to 1945 – the Charter of the United Nations. Even more surprisingly, the impression one gets from the book is that the Charter has not added much to the revolution triggered by the 1928 Pact. The point here is not so much whether the rule prohibiting the use of force had already crystallised as a rule of general international law before the adoption of the United Nations Charter. The point is that, in the book’s narrative, all the major instruments for enforcing that prohibition – the non-recognition of territorial acquisitions gained as a consequence of the use of force, the possibility of having recourse to economic sanctions against an aggressor state, the individual crime of aggression – were already available, and had actually been used by states, when the Charter was adopted. Admittedly, the authors recognise that the main innovation introduced by the Charter was represented by the establishment of a centralised system for enforcing peace. Indeed, in their account, Shotwell’s intuition was exactly that: ‘write the Pact into a new treaty – and then build an enforcement structure up around it’.^{Footnote 5} However, the centralised system for enforcing peace established by the Charter receives scant attention in the book. In particular, little is said about the expectations that this system generated at the time of its adoption and that, in a certain measure, continues to generate today. In the narrative of the book, as we will see, the role generally assigned to the UN collective security system is almost entirely occupied by a different, and more indefinite, method, the ‘outcasting’ of an aggressor state. The consequence is that, in the end, it becomes unclear what the real contribution of the Charter to the shaping of the New World Order has been, apart from consolidating the legal revolution brought about by the Peace Pact.

The authors’ attempt to shed new light on the importance to be assigned to the Peace Pact is certainly admirable and in many respects convincing. By contrast, the book does not appear to do enough to stress the importance of the San Francisco Conference as an historical turning point. However, it is hard to depart from the idea that the UN Charter, more than any other treaty, represents the foundational treaty of the New Legal Order. Obviously, the UN Charter did not come out of thin air. Behind Article 2(4) there was the Peace Pact; the collective security system established under the Covenant of the League of Nations provided a source of inspiration for the mechanism set forth under Chapter VII of the Charter. But the fact is that it was only with the UN Charter that the rule prohibiting the use of force was associated with a system of international security ‘which displayed the highest degree of centralization reached until that time in the history of international law’.^{Footnote 6} In matters of peace and security, the New Legal Order appears to rest on two pillars, and not just one: the prohibition of states to use force and the existence of a centralised system of collective security which, with the sole exception of self-defence, confers upon the Security Council the monopoly of the lawful use of force. In scholarly as well as in states’ perception, it is this combination of a legal obligation with a centralised procedural mechanism essentially based on the political assessment of states that, for good or bad, characterises the contemporary approach to the problem of war.^{Footnote 7} The UN Charter embodied, and continues to embody, both pillars. The centrality accorded to the Charter in the New Legal Order is reflected in the countless number of treaties concluded after 1945 that express forms of deference to it.^{Footnote 8} It is also reflected in the choice made by a number of states to ‘internalize’ the two pillars of the New Legal Order in their domestic constitutions.^{Footnote 9} True, with the beginning of the Cold War, the great expectations generated by the Charter were rapidly frustrated. States’ perspectives over this treaty have changed over the time. The collective security system itself has undergone a process of transformation in order to adapt to changing circumstances. However, the basic coordinates that still dominate the current reflections on the legality of the use of force remain those established by the Charter in 1945.

III. Enforcing peace: Unilateral or centralised response?

As already observed, The Internationalists says almost nothing about the powers of the Security Council or about its actual role in enforcing peace. While the book refers to a number of crisis situations that have arisen in the recent practice, the selection does not include situations in which the Security Council appears to have played a major role. From time to time, The Internationalists expresses a certain scepticism about the capacity of this organ to deal effectively with international crisis. The authors observe that, in certain instances, the Security Council ‘has been hamstrung’ by disagreement among its members, and that ‘[t]he permanent five members have been unable to agree to override the protection against the use of force and authorise intervention in either country’.^{Footnote 10} This scepticism is entirely justified. No doubt, the effectiveness of the collective security system is ‘asymmetric’:^{Footnote 11} the system may not be able to work properly or at all, if the interests of the permanent members are directly involved. It remains to be seen whether this is the whole story or whether instead, despite all the deficiencies of the Security Council, there is also a more positive story to be told. This, however, is a point that the book does not address.

What the book does address, instead, is the problem whether, in a legal system where recourse to war has been banned, there are tools to replace war as a way of enforcing international law. The authors’ response is that these tools do exist and prominently include non-violent outcasting.^{Footnote 12} Space limitations preclude a detailed analysis of the sophisticated theory of law-enforcement through outcasting that Hathaway and Shapiro develop.^{Footnote 13} I limit myself to raising one point, which concerns the relationship between peace-enforcement through the UN collective security system and law-enforcement through outcasting. While in many respects the two mechanisms may be regarded as complementary, one can also detect a fundamental tension. The UN system is based on the centralisation of the function of peace-enforcement. It requires cooperation among states and relies on the possibility of reaching political compromises, primarily among its permanent members. While the need for cooperation enhances the legitimacy of the system, it also imposes high costs in terms of effectiveness when such cooperation is lacking. Outcasting is a more flexible mechanism. While it recognises the importance of institutions or adjudicative bodies in the law-enforcement process, it also admits the possibility of unilateral responses coming from groups of states acting as law-enforcing agents by means of economic sanctions or other tools, the only limitation being that these tools are to be non-violent ones. Outcasting based on unilateral responses from groups of like-minded states may be highly effective in enforcing law. The risk it brings, however, is that of abuse and of further destabilisation of interstate relations. In certain situations, it also risks undermining the authority of the Security Council.

The coexistence between a centralised peace-enforcement mechanism and a decentralised law-enforcement system is a delicate one. They may complement each other or may be regarded as alternative ways by which states can address situations that threaten peace and security. However, one may also take a more radical view and find that these two systems are substantially incompatible given the fundamental tension that affects their relationship and the difficulty of finding adequate mechanisms for managing their coexistence. The debates surrounding the work on the Articles on State Responsibility show how this issue was highly controversial within the International Law Commission; in fact, it continues to be highly controversial among states. With the progressive recognition that there are fundamental values of the international community and that states are legally entitled to act for the protection of these values, the problem of enforcing compliance with these fundamental values has become central. Several states opposed to the possibility of having recourse to third party non-forcible countermeasures, claiming that a rule admitting this possibility ‘has no basis in international law and would be destabilizing’ and that ‘countermeasures in response to violations of community obligations should be taken through the United Nations, or that at least there should be a reference to Security Council action’.^{Footnote 14} It may be interesting to note that, more recently, Russia and China have also stressed the fact that recourse to unilateral sanctions may undermine the authority of the Security Council.^{Footnote 15}

Admittedly, it would not be correct to regard the emphasis placed by the book on outcasting as a plea in favour of unilateralism. The book simply does not develop this point. For the reasons mentioned above, this decision may be understandable. How to manage the tension between unilateralism in law-enforcement and centralisation in peace-enforcement remains, however, a central issue. Its significance seems to go well beyond the current debate on the permissibility of third-party countermeasures. On a broader perspective, these two approaches appear to point to different modes of development of the international legal system.

IV. The UN and the future of the outlawry of the war

In the concluding chapter of The Internationalists, suggestively entitled ‘The work of tomorrow’, Hathaway and Shapiro warn that ‘the postwar consensus on the illegality of war is under greater assault today than it has been in seven decades’.^{Footnote 16} It is difficult not to agree with the two authors. States, particularly the United States and its Western allies, have increasingly advanced broad interpretations of the scope of the rule on self-defence; some of them have claimed the existence of an exception to the prohibition to the use of force in cases of grave humanitarian crisis; they have even attempted to dilute the requirement of an authorisation by the Security Council by relying on implausible interpretations of previous authorisations or by pretending that they were acting on the basis of a tacit or implicit authorisation. Against this trend, the authors urge America and its allies to maintain their commitment to the ‘rules and institutions’ that underlie the New World Order, including by supporting the United Nations.^{Footnote 17}

My last comment relates to this reference to ‘rules and institutions’. In particular, it focuses on the relationship between the prohibition to use force and the peace-enforcement mechanism established by the UN. The question is whether, and to what extent, the well-functioning of the UN peace-enforcement mechanism is important for preventing the system from developing new and broader exceptions to the rule prohibiting the use of force. The book is not without its ambivalence on this point. Indeed, if the system is able to work by relying on non-violent outcasting, as suggested by the authors, it may be thought that economic sanctions and other forms of outcasting may well replace a mechanism, such as the one established by the UN Charter, that in so many instances have proved to be ineffective.

The relationship between the UN peace-enforcement mechanism and the prohibition to use force has long been debated in legal literature. Several authors have expressed the view that the effectiveness of the rule is strictly dependent on the effectiveness of the institution. Almost 50 years ago Franck famously announced the death of Article 2(4) of the Charter as a consequence of the fact that the system of collective security established by the Charter was not able to work.^{Footnote 18} This view certainly went too far. There is no such automatic correlation between the functioning of the mechanism and the validity of the rule. At the same time, however, the existence of a certain linkage can hardly be denied. As two authors cautiously put it, ‘whenever the system of collective sanctions provided in the UN Charter does not function properly, States might find it difficult to fully comply with Art. 2(4)’.^{Footnote 19} The fact is that the legal regime established by Articles 2(4) and 51 of the Charter sets a very rigid limitation to states. This is not without its side effects.^{Footnote 20} States may be willing to abide by the system as long as the system is perceived to be able to adapt to the changing circumstances and to cope with the new challenges. In this respect, many different reasons may be given to explain why the legal regulation on the use of force set forth by the Charter appears nowadays to be under pressure. Among them, there is no doubt the difficulty of coping adequately with certain new threats to international security, in particular those coming from transnational networks of terrorist groups. One may also detect an endogenous reason, which is linked to the transformation of the international legal order. As was briefly mentioned before, the recognition that there are ‘communitarian values’ of the international community and that all states may act as law-enforcement agents to protect them on behalf of the international community brings with it great expectations that compliance with these values will be enforced; at the same time, it renders it less acceptable to renounce the undertaking of enforcement measures in the name of maintaining international peace. The debate over the lawfulness of the humanitarian intervention is the clearest illustration of this point.^{Footnote 21}

To be clear, this claim should not be taken as suggesting that the prohibition set forth in Article 2(4) is obsolete or that it must be overcome. To the contrary, I entirely subscribe to the view that it remains a central rule of the international legal system. In my view, however, it is hard to imagine of an effective rule prohibiting the use of force without an effective institution which is capable to respond to new challenges, thereby attenuating the ‘side effects’ deriving from the rule’s rigidity. In this respect, it may not be enough to emphasise the importance of the rule, as Hathaway and Shapiro have admirably done. The role of the institution should also be adequately stressed. This link between rule and institution, however, does not emerge as clearly as it might from the book. From my perspective, this is a missed opportunity. The book’s central message – a defence of the prohibition on the use force – could have been stronger if it would have been accompanied by a defence of the authority of the United Nations and of its centralised mechanism for enforcing peace.