6. Every endeavour in comparative constitutional law needs to justify the criteria according to which jurisdictions have been selected for discussion. What is more, the way research questions are framed may also lead to an exclusion of constitutional systems in which these questions are not askedor in which they are asked in such a different way that it becomes difficult to draw comparisons. The main questions identified for this entry have a strong resonance with constitutionalist systems which are organized according to some form of the separation of powers. What is more, the questions pertaining to democracy and the rule of law also exclude the consideration of jurisdictions in which these constitutional ideals are not embodied. Hence, there is a strong risk to fall into the trap of a self-referential, liberal, and Western mindset which takes discussions in a few jurisdictions of the ‘Global North’ as being representative of the broader global picture. The risks pertaining to this selection bias are flagged so that the reader can draw his or her own conclusions. At the same time, the debate about the limits of international cooperation flowing from democracy and the rule of law is also mimicked in jurisdictions many would not consider to be liberal democracies. In some cases, there is evidence of an unexpected form of learning process.
7. In addition, there is another reason for the focus of this contribution on certain jurisdictions from the ‘Global North’. From a survey of the existing literature, it appears that a proper academic sub-discipline of ‘foreign relations law’ has only emerged in a limited number of jurisdictions. These are, first of all, the United States (US), the United Kingdom (UK) (with the addition of a number of other Commonwealth and Common Law jurisdictions), France, and Germany. There is also a substantive body of literature on the foreign relations law of the EU. Yet, even in the typical list of candidates for expansion of comparative law scholarship beyond this circle—such as India, Israel, and South Africa—to the knowledge of this author there exist no specialized treatises or monographs devoted to this field. While this entry is not the right place to remedy this deficit, wherever possible the discussion will also draw on constitutional provisions, case law, and contributions from the literature pertaining to these jurisdictions. Looking beyond this entry, it is certainly a desideratum to see more scholarship develop about the foreign relations law of jurisdictions from non-Western states. In any case, the prevailing focus on a number of Western jurisdictions in this field is also an example of the power dynamics with respect to the production of scholarly knowledge. Key categories for academic debate are developed against the background of specific jurisdictions, with their at times quite idiosyncratic institutional set-ups and developments. This holds true, in particular, for the foreign relations law of the US. The academic debate on US law in this area is highly influential for the global academic community. Yet, very few systems actually borrow from the US experience, at least not directly.
8. The topic of this entry also needs delimitation from other questions. In constitutional law terms, the entry ‘foreign affairs’ translates most easily into the category of ‘foreign relations law’. This notion is usually understood to refer to all those constitutional rules which are meant to determine the conduct of foreign relations of a given state—ie its participation in forms of traditional diplomacy and forms of cooperation in the context of international and supranational organizations. It also relates to the respective roles of different organs of states in international law-making processes—ie the question of the treaty-making power, or which organ of state is entitled to express the opinio iuris of the state for the sake of the formation of customary international law. Beyond these questions, there is debate on the contours of this field of law. Whereas some count questions pertaining to the status of international law—and EU law—to be part of the field of foreign relations law (Henkin 198), others exclude them as they refer to the interaction of different fields of the law (Giegerich para. 3). The divergent views on this matter may have something to do with broader conceptual choices relating to the relationship between international and domestic law.
9. The long-established and somewhat exhausted debate about dualism / monism as organizing principles for the relationship between international and domestic law may no longer adequately express the varieties of law in all of its contemporary complexities (von Bogdandy 397). Yet, the categories linger on as basic organizing principles to conceptualize the interplay of law from different sources. Those who lean more towards a monist understanding of the relationship between international and domestic law are disinclined to view the domestic constitutional law rules on the status of international law as part of the field of ‘foreign relations law’. According to this perspective, this view resembles the tradition of this notion in both German and US American constitutional law, where it was often used as a kind of Ersatz international law, although one which is firmly rooted in the domestic legal order (critical in this regard is McLachlan (2014) 1.30). In contrast, authors who follow a more traditional, dualist framework would have no problems in understanding the ‘Supremacy Clause’ of the US Constitution (Constitution of the United States of America: 17 September 1787 (as Amended to 7 May 1992) Art. VI, Clause 2 (US)) or Arts 25 and 59 of the German Basic Law (Basic Law of the Federal Republic of Germany: 23 May 1949 (as Amended to 23 December 2014) (Ger)) as parts of the ‘foreign relations law’ of the respective system, since in their view it must ultimately be the domestic legal system which determines the status of international law (Schorkopf section 3, para. 1).
10. Regardless of this debate about the scope of ‘foreign relations law’, it is important to uphold a clear distinction between the rules of public international law proper and the domestic constitutional law of a given system. ‘Foreign relations law’ is domestic law. From a doctrinal perspective it cannot be framed as a replacement of international law, and from a policy perspective it should not, because otherwise the integrity and independence of international law would be endangered.
11. This does not stand in the way of linking the study of foreign relations law with the nascent stream of literature engaging in so-called ‘comparative international law’ (Koskenniemi 1; Roberts 57). Authors engaged in this project study the specificities of how international law is made, shaped, and applied in various domestic situations (Roberts, Stephan, Verdier, and Versteeg 469). They thus aim at contextualizing the workings of international law. For this endeavour, the respective foreign relations law of domestic constitutional systems can yield valuable insights, since different approaches towards international law will, in many situations, be conditioned by domestic constitutional systems. Conversely, the study of foreign relations law will benefit from a comparative perspective on how international law is introduced into different legal systems, thereby contributing to a questioning of orthodox views within the respective legal system.
12. More generally, foreign relations law need not be limited to constitutional law. It can also be based on statutory law, administrative regulations, and other legal sources. The concrete conduct of a state’s foreign affairs can often be owed to a complex interplay of different legal sources. What is more, the conduct of the foreign affairs of a given state is, of course, also influenced by political considerations which may limit the recourse to certain options a given constitutional system might provide for. It can even be asked whether foreign relations law is more strongly affected by political considerations than other branches of constitutional law. Asking this question takes us back to the starting point of this entry, ie the question of whether the external sphere of states is necessarily subject to different rules than the internal sphere. However, while the conduct of foreign affairs is necessarily a politically charged endeavour, this should not lead to a simplistic and binary view which understands domestic affairs as less political in comparison. Rather, the specificities of the conduct of foreign affairs relate to the fact that, in foreign affairs, the conduct of other political actors also needs to be accounted for. It is not just the domestic political process which impacts on constitutional law, but rather a combination of various factors and external forces which may make the application of the law less predictable and will, in turn, also limit the available policy options for many actors.