As we have seen, various kinds of tension may arise between trade and environmental protection in the Community and United States legal orders. The objective of Part 1 is to discuss and compare how, through their power to review state (environmental) measures interfering with trade, the Court of Justice and the Supreme Court have attempted to reconcile these tensions.

Part 1 is divided into four chapters. Chapter 1 first discusses the principle of free intra-Community trade as it is established and protected by the EC Treaty and interpreted by the Court of Justice in its case law. It then discusses the case law of the Court of Justice dealing with trade-restrictive member state environmental measures. Chapter 2, which is devoted to United States law, follows the same structure as chapter 1. First, it discusses the development by the Supreme Court of a principle of free trade between states. It then discusses the Supreme Court cases dealing specifically with trade-restrictive state environmental measures. Chapter 3 consists of a comparative analysis of the findings made in chapters 1 and 2. First, it draws a parallel between the case law of the Court of Justice and of the Supreme Court in so far as they establish and protect a principle of free interstate trade. It then compares the case law of these courts specifically dealing with trade-restrictive state environmental measures.