June 2000 - Empirical evidence supports the hypothesis that when tariffs and export taxes are important sources of revenue for developing countries, and when those countries have narrow tax bases and high tax rates, trade liberalization will come about when the governments diversify their revenue sources through efficiency-enhancing, revenue-increasing tax reform. That free trade allows economies in an ideal world to achieve the greatest possible welfare is one of the few undisputed propositions in economics. In reality, however, free trade is rare. Kubota argues that many developing countries intervene in trade at least partly to raise revenues and that episodes of trade liberalization are often linked to tax reform. She proposes a formal model to explain why developing countries rely disproportionately on tariffs for government revenues, when tax reforms are expected, and under what conditions trade liberalization will take place. The model uses the simple concept of the fixed costs involved in tax collection. When fiscal needs are limited and the infrastructure to monitor, administer, and collect taxes is not well-developed, it is optimal for governments to rely on a handful of easy-to-collect taxes, which generally includes trade taxes. When fiscal needs expand, the excess burden on the tax base grows rapidly, and tax reform becomes necessary. Tax reforms reduce reliance on the existing tax base, often allowing the statutory tax rate to be lowered. This is a form of trade liberalization when it involves the trade sector. Kubota defines trade liberalization in a somewhat unconventional way: only reductions in the rates at which the trade sector is taxed are considered trade liberalization. Tariffication of quotas, normally considered a form of trade liberalization, is treated as tax reform (expanding the tax base). Kubota tests this hypothesis empirically, first through three historic case studies (Bolivia, Jamaica, and Morocco) and then through systematic econometric analysis. She constructs a set of panel data for 38 developing countries for 1980-92, using the statutory tariff rates published by UNCTAD. She uses empirical tests to isolate the cause of trade liberalization. The results support her hypothesis: tariff rates are positively related to fiscal shocks and negatively associated with episodes of tax reform. This paper - a product of Trade, Development Research Group - is part of a larger effort in the group to investigate the role of trade taxes in government revenues in developing countries. The author may be contacted at kkubota@worldbank.org.