Opening markets in network industries to competition is challenging. This chapter compares how such challenges have been addressed by the two most remarkable trade liberalization regimes—the internal market project of the European Union (EU) and the trade agreements of the World Trade Organization (WTO). The chapter proposes a threefold framework to narrate the evolution of the EU and the WTO since their foundations—namely, the animating principles underlying the rules of market access, the procedural rules for enforcement, and the harmonization alternative. The results reveal that the different approaches to promoting market access and competition in the network industry find justification in the differences in institutional capabilities. These differences have enabled the EU to adjust its economic governance across time better than the WTO.