From Arnaud Costinot, Dave Donaldson, Jonathan Vogel, Iván Werning:
The theory of comparative advantage is at the core of neoclassical trade theory. Yet we know little about its implications for how nations should conduct their trade policy. For example, should import sectors with weaker comparative advantage be protected more? Conversely, should export sectors with stronger comparative advantage be subsidized less? In this paper we explore these issues in the context of a canonical Ricardian model. Our main results imply that optimal import tariffs should be uni- form, whereas optimal export subsidies should be weakly decreasing with respect to comparative advantage, reflecting the fact that countries have more room to manip- ulate prices in their comparative-advantage sectors. Quantitative exercises suggest substantial gains from such policies relative to simpler tax schedules.