The GATT/WTO Article XXIV prevents a customs union (CU) from raising its common external tariff. In this paper, we compare CU formation with and without this Article XXIV constraint. We show, in a multi-country oligopoly model, that for a given CU structure, Article XXIV improves world welfare...

This paper identifies a new terms-of-trade externality that is exercised through tariff setting. A North-South model of international trade is introduced in which the number of countries in each region can be varied. As the number of countries in one region is increased, each government there...