The Trail Smelter arbitration occupies an ambiguous place in history. On the one hand, scholars revere it for being the first of only a few landmark cases that address transboundary pollution. On the other hand, scholars are prone to dismiss the case as a relic of a bygone era. The arbitration resolved itself thirty years before international environmental law was even in its nascent stages, and the case arose under unique circumstances when science had yet to reveal the threat human activities pose to the environment. Although praised for acknowledging the “no harm” principle, environmentalists lament the decision's implicit recognition of a right to pollute, “so long as the polluting activities do not cause ‘damage’ in the sense of direct injury … to a second state.”
Those scholars whose assessment of the Trail Smelter arbitration's place in history is less than generous, explain that times have changed. We are told that the Trail Smelter arbitration has limited modern applicability because many of the world's environmental problems no longer fit into Trail Smelter's traditional conception of transboundary pollution. States and other actors have turned away from resolving environmental disputes through adjudication, and instead have created elaborate regulatory regimes designed to address environmental concerns. The troubling aspects of the Trail Smelter arbitration, which appear to endorse a right to pollute, have been forgotten. For many commentators then, the basic teachings of the Trail Smelter arbitration are of marginal relevance to modern international environmental law.