ASAT-Isfaction: Customary International Law and the Regulation of Anti-Satellite Weapons

This article asserts the thesis that customary international law (CIL), even in the absence of any new treaty, already provides a legal regime constraining the testing and use in combat of anti-satellite (ASAT) weapons. This argument, if validated, is important for both legal and public policy considerations: the world (especially, but not only, the United States) has grown increasingly dependent upon satellites for the performance of a wide array of commercial and military functions. At the same time, because of this growing reliance (and hence vulnerability), interest has surged in developing novel systems for attacking a potential enemy's satellites - ASAT technology has been tested by the United States, Russia, and China, and other countries may soon shoot up that same dangerous trajectory. Oddly, the United States has consistently opposed international efforts to negotiate an arms control solution to this problem. Any comprehensive treaty would certainly be difficult to reach (there are numerous complicated issues of definitions, scope, and verification to surmount) but the American stance (not only during the Bush Administration) has been that we should not even try, because "there is currently no arms race occurring in outer space." This article turns that resistance on its head, by asking whether customary international law, even without any formal treaty on point, already imposes meaningful constraints upon ASAT activities. To develop the argument, it analyzes three strands of CIL: first, "general" customary international law, which has long been recognized as an authoritative, albeit complex, source of binding rules; second, the specialized legal regime incorporated into the law of armed conflict, which imposes its own strictures, fully applicable to conventional warfare, but not yet applied extra-terrestrially; and finally, another realm of specialized CIL, the emerging jurisprudence governing international environmental law. My conclusion is that there is already a meaningful ASAT-control regime, created by CIL even without codification in a new treaty. This is not, to be sure, a fully comprehensive legal web, and there would still be plenty of additional scope for a new treaty to enhance and extend the legal regime. But the conclusion is that treaty negotiators would not be drafting on a complete tabula rasa; an incipient legal order is already in place.