This address considers international law and the success and scope of the international system created by the United States in the aftermath of the Second World War. It then considers its biggest challenge and perhaps failure - climate change, thereby demonstrating the limits of this system. International environmental law has had successes, including phasing out the chemicals that caused damage to the ozone layer. Yet when confronted by a problem with an ostensibly extended time horizon and entailing vast short term costs, thinternational community has been unable to halt a disaster now in progress.