Network Effects of Tariffs

We develop a model in which country-specific tariffs shape trade flows, prices, and welfare in a global economy with one homogeneous good. Trade flows form a Directed Acyclic Graph (DAG), and tariffs influence not only market outcomes but also the structure of the global trade network. A numerical example illustrates how tariffs may eliminate targeted imports, divert trade flows toward third markets, expose domestic firms to intensified foreign competition abroad, reduce consumer welfare, and ultimately harm the country imposing the tariff.