The International Law Commission of the United Nations is currently studying a topic entitled “International Liability for Injurious Consequences Arising out of Acts Not Prohibited by International Law” (hereinafter “international liability” or “topic”). That topic has proven to be as serpentine as its title suggests and consequently is difficult to define. It is generally understood as encompassing, in particular, harmful transnational environmental effects of internationally lawful activities. This aspect alone has made the topic increasingly important, as demands on resources have intensified, technological advances have given rise to threats of widespread and even catastrophic transboundary harm, and the international community has grown more interdependent in other ways.