The recent article by Marco Verweij in Law and Society Review offers a promising approach for studying the effectiveness of rules for achieving environmental goals. He suggests treating levels of toxic substances as the independent variable, and then looking at that variable across a range of legal and regulatory cultures. In the article, he argued that the adversarial culture of the United States compared to the cooperative culture in civil law nations meant that firms in Europe were more proactive in cleaning up their emissions than was the case in the United States. To make this point, he sought to compare chemical pollution in the Rhine to that found in the Great Lakes of North America. He also claimed that the International Joint Commission (IJC), a small-but-respected international organization, had worsened the situation in the Great Lakes. Verweij's approach is so promising, but the execution so flawed, that a comment on his thoughtful effort seemed in order. My comments will address, first, the scientific/technical difficulties in his study and, then, political/social science issues. It concludes with a brief review of other ways we could test his idea. I believe correcting the flaws related to the biophysical science and executing a relevant study along the lines he suggests would advance our understanding of how differences in legal cultures and institutions produce real-world outcomes.