Without modification, the World Trade Organization's Agreement on Sanitary and Phytosanitary Measures (SPS Agreement) will become the battleground for many complex agricultural trade disputes. There are two interrelated reasons for this. The first reason is that the agreement confers on members considerable unilateral power to implement unchallengeable market access barriers to agri-food imports, provided those members have a legitimate justification to do so. The second reason is that much ambiguity continues to exist regarding what properly constitutes a legitimate justification. Therefore, modifications to the SPS Agreement are required to fully characterize a legitimate justification, thus ensuring that SPS-related market access barriers will be wielded in a manner consistent with ensuring public health while preventing unnecessary trade distortion.