This paper studies the impact of a WTO withdrawal of trade concessions against countries
that fail to respect globally recognized environmental standards. We show that a punishing
tariff can be effective when environmental and trade policies are endogenous. When required standards lie within a reasonable range, compliance along with free trade as a reward is the unique equilibrium outcome. A positive optimal tariff in the case of non-compliance prevents pollution-motivated delocation, but only works as a successful credible threat and does not emerge in equilibrium. Results are consistent with broad empirical evidence that disputes the pollution haven hypothesis and suggests capital movements to be non-pollution related
