The recent WTO dispute case, Korea – Import Bans, and Testing and Certification Requirements for Radionuclides (Korea – Radionuclides), illustrates complex legal issues and significant political implications associated with the regulatory autonomy of a sovereign country under the WTO Agreement on Sanitary and Phytosanitary Agreement (SPS Agreement). There has been constant tension between the sovereign right of a WTO member state to determine its own appropriate level of protection (ALOP) and the regulatory constraints imposed under the SPS Agreement to prevent abuse and disguised trade protection. The case emerged from this tension and raises questions on the extent of the regulatory autonomy in the application of an SPS measure. This article addresses these questions and examines the criteria for the qualitative standards for the ALOP, the question that the Appellate Body decision did not fully resolve. The criteria for the qualitative ALOP standards affect the regulatory autonomy significantly under the current SPS rules as it determines the manner and the extent of which a Member may meet the sensitive public interests in the application of an SPS measure. The article proposes a rational basis test to restrain abuse of SPS measures while preserving the regulatory autonomy protected under the SPS Agreement.