The interpretation of GATT Article XX has begun to play a critical role in defining the relationship among international trade law, international environmental law, and general international law. Different thresholds for provisional justification of trade measures under paragraphs XX(b) and (g) suggest that each paragraph should address different types of policies and measures. However, jurisprudence on paragraph XX(g) appears to make paragraph XX(b) somewhat redundant and raises the issue of whether paragraphs XX(b) and XX(g) have been interpreted in accordance with the rule of effective treaty interpretation. This article develops an analytical approach to take in deciding whether to address a trade measure under GATT paragraph XX(b) or (g), based on the proximity of interest between the country that applies trade restrictions and the environmental or health problem that is addressed. I propose that the subject matter be assigned based on the location of the environmental concern, with domestic concerns addressed in XX(b) and transnational or global concerns under XX(g). An analysis of Article XX, applying the rules of treaty interpretation of the Vienna Convention, supports this interpretation. The adopted body of GATT and WTO jurisprudence also supports this interpretation, with the exception of one case.