The trade paradox persists under excise taxes

Brander and Krugman (1983) and Sertel (1988) followed by Krugman (1989), showed two sides of a ‘trade paradox’: The paradox in competition, viz. that opening trade (or increasing competition) may cause welfare to decline, and the paradox in efficiency, viz. that an increase in unit transport cost may increase welfare. In this paper, we consider the situation in an environment where interventionist trade policies are not permitted but each country is sovereign to impose an excise tax (or subsidy). The paradoxes persist under equilibrium excise taxes, reckoned both at the non-cooperative (Nash or dominant strategy) equilibrium and at the cooperative solution among tax-imposing authorities maximizing welfare. We also see that the paradoxes persist in a taxless environment where market equilibrium is Stackelberg rather than Cournot.