This paper investigates the relationship between trade openness and the size of governments, both theoretically and empirically. We argue that openness can increase the size of governments through two channels: (1) a terms-of-trade externality, whereby trade lowers the domestic cost of taxation, and (2) the demand for insurance, whereby trade raises risk and public transfers. We provide a unified framework for studying and testing these two mechanisms. Our main theoretical prediction is that the relative strength of the two explanations depends on a key parameter, namely, the elasticity of substitution between domestic and foreign goods. Moreover, while the first mechanism is inefficient from the standpoint of world welfare, the second, instead, is optimal. In the empirical part of the paper, we provide new evidence on the positive association between openness and government size and we explore its determinants. Consistent with the terms-of-trade externality channel, we show that the correlation is contingent on a low elasticity of substitution between domestic and foreign goods. Our findings raise warnings that globalization may have led to inefficiently large governments.

We show how, in general equilibrium models featuring increasing returns, imperfect competition, and endogenous markups, changes in the scale of economic activity affect the income distribution across factors. Whenever final goods are gross substitutes (gross complements), a scale expansion raises (lowers) the relative reward of the scarce factor or the factor used intensively in the sector characterized by a higher degree of product differentiation and higher fixed costs. Under very reasonable hypotheses, our theory suggests that scale is skill-biased. This result provides a micro foundation for the secular increase in the relative demand for skilled labor. Moreover, it constitutes an important link among major explanations for the rise in wage inequality: skill-biased technical change, capital-skill complementarities, and international trade. We provide new evidence on the mechanism underlying the skill bias of scale.