Only months after the failure of the WTO Ministerial Conference Seattle, few topics appear to be more important than the relationship between international trade and the environment. With international trade increasingly revolving around large economic blocs such as NAIFTA and the EU, the relationship between the environment and economic integration in a broad sense, including all forms of regional trade liberalization, has become a focal point of interest. At the same time, few issues are as complex and multifaceted as this one. Does economic integration cause environmental deterioration? Does free trade really induce a downward competition of environmental standards?