Although disputes have not led to full interpretation of the major provisions of the agreement, it appears that the SPS Agreement has not led to the ''harmonizing down" of SPS protection that many opponents of free trade have feared. Instead, the wide latitude permitted by the SPS Agreement has allowed national diversity in SPS measures to thrive while also reducing barriers to trade. International standards have not become a straitjacket—rather, they have had remarkably little impact on national SPS protection policies. (The main exceptions are in countries, especially in the developing world, that have not already adopted elaborate SPS protection policies; for those countries, international standards fill gaps and raise—not lower—the level of SPS protection.) The main impact of the agreement appears to be in harmonizing the process by which nations set SPS policies—notably, it is promoting greater use of risk assessment at the national level. More extensive assessment of risks may actually yield greater diversity in national SPS policies. In the paper I also suggest that the novel mechanisms for providing expert advice to WTO dispute panels have been highly effective and have greatly reduced the problems of "advocacy science" that often plague the use of risk assessment in other judicial proceedings. The story—apparent success in imposing international discipline that promotes trade while accommodating national diversity—may be a useful guide for solving similar problems that are the mainstay of the "trade and environment" debate.
One measure of the success of the postwar trading system is that tariff trade barriers have declined sharply. But the reduction in tariffs has exposed the many nontariff barriers that remain, and in many cases governments have kept protectionism in place by simply shifting from tariff to nontariff measures. Included in the broad category of nontariff barriers are differences in technical standards such as labeling requirements and environmental regulations. The focus in this paper is on one subset of these technical barriers: measures for sanitary (animal, including human) and phytosanitary (plant) protection.
SPS measures often have huge effects on trade; yet managing them is not easy. SPS measures vary across and within nations because preferences and circumstances vary. Some nations seek tight protection while others readily consume riskier foods; some pristine environments are vulnerable to pest infestations and require elaborate quarantines for imported products, but other countries are already overrun with pests. The political and technical challenge for advocates of free trade is to accommodate such differences while stripping away SPS measures that are merely disguised protectionism.
In this paper I examine the effectiveness of the 1994 WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement), which is the most significant global effort to reduce trade distortions caused by differences in national SPS protection policies. I examine the major elements of the SPS Agreement and the three international SPS standard-setting processes that are explicitly mentioned in the SPS Agreement. I briefly consider two other