We value very much David Schneiderman’s excellent comments on the introductory chapter of our edited volume, Ruling the World.
Our goal was neither to be normative in the sense of saying what should be, nor to be comprehensive in the sense of including all important international law in the category of “international constitutional law.” We tried to devise a distinct definition of “constitutional” law at the international level. It seemed to us that a strong analytical framework might be undermined if we tried to include in “constitutional law” all international law that is important, or morally compelling. In other words, we wanted to develop an approach that could distinguish between a highly legalized international order and a constitutionalized international order.
In our view, then, it became necessary to narrow what we term “constitutional” at the international level, in order to produce an analytically distinct category. Like Schneiderman, we worried that the category became too narrow, and so, included the broader category of “supplemental constitutionalization” to include international rules that addressed issues that are ordinarily addressed by domestic constitutional law, but where the effect of the domestic constitutional norms became jeopardized by globalization. Efforts to introduce ‘due process’ protections into the Security Council sanctions procedures are, for us, an example of “supplemental constitutionalization.” Thus, our functional approach includes a satisfyingly open and potentially large category, albeit one that raises some analytic concern when compared to the more conceptually discrete, and defensible, categories of enabling and constraining constitutionalization. Having said that, it follows that international investment norms, like international trade norms, do not necessarily fall into the category of “supplemental constitutionalization.” Many rules of international trade law and international investment law, such as rules not to raise tariffs over a specific bound rate, or rules not to impose performance requirements, are “ordinary” international law rules that simply restrict the discretion of states. That domestic constitutional norms similarly restrict the discretion of states does not make international investment or international trade law “constitutional” at the international level. To make this analytic leap is to turn virtually all of international law into international constitutional law. Our functional approach, in contrast, insists on this analytical “levels” distinction: international constitutional law consists primarily of rules that govern (or restrict) the production of international law.
Schneiderman raises an important point about the politics of international constitutionalization. We agree with him that labeling international investment law (or international trade law) “constitutional” can be an effort to privilege those norms over other norms, such as human rights, and Dunoff’s chapter on the WTO pursues this argument at some length. Indeed, this is one of the reasons we thought it important to develop a mechanism that would decline to term these types of rules as “constitutional” at the international level, even though they may perform a restraining, or even constitutional, function at the domestic level. Thus, one important virtue of limiting the label “constitutional” to those secondary rules that govern the production of other international norms is that it leaves open for contestation the controversial normative and political issues Schneiderman raises, such as the relationship between trade and human rights law, as opposed to trying to resolve these issues through definitional fiat.
Moreover, our additional category of supplemental constitutionalization allows certain core constitutional functions that are challenged by globalization, such as perhaps human rights, to be privileged by inclusion within the category of international constitutional law. The distinguishing feature for this category, then, is one of constitutional subsidiarity: since it is no longer possible adequately to carry out these constitutional functions at the domestic level, it becomes necessary to carry them out at the international level.