Abstract
Even though widely recognized as one of the core disciplines of international economic law, the interpretation of national treatment (“nt”) obligation has been long marked by legal indeterminacy. More recently, a series of landmark cases, including us—Clove Cigarettes, us—Tuna ii (Mexico), us—cool and ec—Seal Products, have fundamentally reshaped our collective understanding of the nt obligation in the gatt/wto system. The objective of this article is to take stock of what we have already known about the nt obligation in the wto law, identify the lingering uncertainties and discuss the options for the wto Appellate Body to bring more clarity to the nt obligation in future dispute settlements.