Since the 1980s, the development strategies adopted by many emerging countries have gone against ‘orthodox’ policies and been subsumed under the concept of the ‘developmental state’, which was inspired by the experience of East Asian states. The paper evaluates this concept of developmental policies and investigates the conditions that lead to their success or failure, in particular the existing relationships between states and markets, through a comparison between examples from post-communist Russia and Sub-Saharan African states since the 1980s onwards. The paper shows that Asian policies have been developmental because they could meet two conditions - national economic guidance and industrialisation -, which explains their success. It demonstrates that though for different reasons, they were met neither by Sub-Saharan African states nor Russia. This comparison shows the importance of causal channels and constraints that have so far remained under-investigated by the literature on developmental states: i.e. that even if there is a political will towards developmental policies, the latter may be impeded by economic structures and political economy, such as the existence of rents and their detrimental incentives, and the externality of policy - more devised by supranational institutions than governments. The paper thus elaborates a typology of statemarket relationships that explains variations in developmental policies’ effectiveness, via two main types of causalities: i) policy externalisation via the conditional lending of international financial institutions is a key constraint on developmental public policies, as it erodes their legitimacy and credibility; ii) rent-based economic structures are not incompatible with developmental policies but may foster deindustrialisation – both channels weakening the accountability of leaders to their citizens (notably the accountability established by taxation). In both Sub-Saharan Africa and Russia, these causal processes have contributed to the formation of economic and political incentives that have eroded the effectiveness of public policies, including developmental policies.