This paper examines the effect of a tariff on long-run growth and welfare in a two-country innovation-led growth model. We show that although raising the home country’s tariff reduces the growth and GDP of the foreign country, it will backfire by depressing R&D and growth of the home country. The Nash equilibrium tariffs can be positive, and they are larger when the government expenditure is more beneficial to private production and/or when the productivity of innovation is higher. The presence of positive Nash equilibrium tariffs provides a theoretical explanation for why countries have incentives to implement a tariff policy regardless of its negative effect on growth. Finally, the Nash equilibrium tariffs are higher than the globally optimal tariffs, that is, the levels that maximize the joint welfare of both countries.

本文研究了关税对两国创新主导增长模型中长期增长和福利的影响。我们表明，尽管提高母国的关税会降低外国的增长和 GDP，但它会因抑制母国的研发和增长而适得其反。纳什均衡关税可以为正，并且当政府支出对私人生产更有利和/或创新生产力更高时，它们会更大。正纳什均衡关税的存在从理论上解释了为什么各国有动力实施关税政策，而不考虑其对增长的负面影响。最后，纳什均衡关税高于全球最优关税，即两国共同福利最大化的水平。