This paper empirically investigates contrasting views on the politics of economic policy. Merging different databases, we test various predictions coming form different strands of literature, with the aim of explaining the cross-sectional and temporal variation in the degree of regulatory intervention and entry liberalization in the digital mobile telecommunications industry of OECD countries during the 1990's. We analyze the role of political institutions, government's types and ideological position, industry and consumers’ private interests, as well as the regulatory environment in shaping regulatory policy. We find strong evidence that all these sets of variables help to explain some degree of variability in the observed liberalization patterns among countries. Yet, political and regulatory institutions and the pressure of strong incumbent firms are found to be the most important factors.