In this paper, two key questions are asked: why has the GATT/WTO worked in terms of multilateral tariff reduction and promotion of global trade, and to what extent will it act as a constraint on economic nationalism? To answer these two questions, three themes are laid out in the paper: first, the seminal economic model rationalizing the economic logic of the GATT/WTO is assessed; second, the perceived relevance of the GATT/WTO in a world of increasing regionalism is discussed; and third, the robustness of the GATT/WTO legal framework and dispute resolution mechanism is evaluated. The key conclusion of the paper is that the underlying economic logic of the GATT/WTO is still relevant, but that enforcement of the cooperative agreement will likely be placed under significant strain with threat of increased protection, and even a potential trade war.