This paper argues that an unequal distribution of political power, biased to landed elites and owners of natural resources, in combination with openness to trade is a major obstacle to development of natural resource- or land-abundant economies. We develop a two-sector general equilibrium model and show that in an oligarchic society public investments conducive to industrialization - schooling for example - are typically lower in an open than in a closed economy. Moreover, we find that, under openness to trade, development is faster in a democratic system. We also endogenize the trade regime and demonstrate that in a land-abundant economy the landed elite has an interest to support openness to trade. We present historical evidence for Southern economies in the Americas that is consistent with our theoretical results: resistance of landed elites to mass education, comparative advantages in primary goods production in the 19th century globalization wave, and low primary school enrollment and literacy rates.