This thesis brings together three contributions to ongoing debates in the field of trade policy and international relations. The first chapter studies whether trade has a pacifying effect on interstate relations, disentangling the effects from imports and exports. A political economy model shows that exports have a pacifying effect, while imports foster hostilities. The second essay examines the effects of export restrictions on international prices. Proposing a gravity model for prices and presenting a new database on Export Restrictions in Agriculture, we focus on cereals and oil seeds and find sizable effects on prices in Maize and Soybeans markets, but no detectable effects on Wheat and Rice. The final chapter explores the consequences of product aggregation in the structural gravity model, showing that complementarity between the goods produced by the origin and those demanded at the destination needs to be controlled for in the structural form of the aggregated model.