Mercosur was born out of the rapprochement of Argentina and Brazil. After a promising start in the 1990s, increasing differences between the two countries spanned from 2003 to 2015, despite positive political and economic conditions for the convergence of their trade policies. This Doctoral thesis argues that these difficulties highlighted important differences between Argentina and Brazil concerning the role of regional integration in their domestic economic strategies, including divergent approaches regarding globalisation. This hypothesis is sustained by a theoretical approach aiming at addressing three levels of analysis: global value chains and new international trade rules; political and social coalitions at national level and the political economy of regional integration in the context of globalization. Globalized economy, analyzed from the perspective of competition for the appropriation of rents, seems to explain the motivations of economic and political actors. Particular incentives and constraints are identified when it comes to the design of trade and industrial policy of economies poorly integrated into global economy. Factions of the industrial sector, formerly inward-looking, change their strategies of appropriation of rents, thus favoring more open national economies. Yet, other sectors, because of their poor capacity to integrate into global value chains, advocate for the continuity of protectionist policies. With regards to regional integration schemes, globalization limites the opportunities for customs union projects based on the development of industrial capacities within national markets. On the contrary, it favors the kind of open integration provided by free trade agreements. From the point of view of trade and industrial policy design, three types of reactions to globalisation were identified: the liberal option, the purely defensive one and the neo-developmentalist policy. The latter, initially chosen by Argentina and Brazil, proved difficult to implement in actual conditions of political and economic upheavals (the stock of 2008-2009) and limited institutional capabilities inherited from pro-market reforms of the 90’. The failure of the neo-developmental experiment and different coalition configurations leads to divergent policy choices : Brazil falls into the liberal option, while Argentina chooses the defensive one. These findings are used to explain the dynamics of negotiations between Mercosur and the European Union and of conflicts within the Mercosur customs union from 2003 to 2015. (POLS - Sciences politiques et sociales) -- UCL, 2019