This article investigates the European Commission's external energy policy through the lens of the regulatory state. It argues that because of the nature of its institutions, policy tools and resources, the Commission remains a liberal actor even as the world leaves the benign pro-market environment of the 1990s and becomes more mercantilist – or ‘realist’. The article tests seven hypotheses related to two key challenges as perceived by the Commission: building energy markets, and making them work. It finds that the Commission seeks to project the single market beyond its jurisdiction to deal with transit infrastructure problems; extend international regimes to cover energy trade; deal with monopolists such as Gazprom through classical competition policy; and fix global energy market failures with clear regulatory state tools. Importantly, however, some actions by the Commission can be seen as an attempt to counterbalance external actors, or as second-best efforts to address energy market failures.