The principle of non-discrimination – the central pillar of the post-World War II trading system – has recently come under threat due to the increasing use of country-specific trade restrictions by members of the World Trade Organization (WTO). These measures significantly distort global trade flows and lead to an unequal distribution of the benefits of trade. It is, therefore, surprising that we know so little about what is driving the choice between discriminatory and non-discriminatory trade barriers. This research project aims to answer this eminently political question by investigating how contemporary trends in international trade (e.g. globalisation of production) affect the position of domestic firms and/or industries vis-à-vis (non)discrimination, and how these preferences translate into trade policies pursued by governments. Starting from an innovative conceptual framework, I derive several testable hypotheses that challenge the conventional wisdom in the literature on trade policy. Moreover, I propose a sequential mixed-methods explanatory design that comprises two stages. First, I will perform a regression analysis of data from seven key members of the WTO (1995-2015). Second, I will conduct eight in-depth case studies, involving document analysis and interviews with political and societal stakeholders.