a1 Associate Professor of Political Science at Columbia University, New York.
Four political models (the international system, rational domestic economic policy, intragovemmental politics, and interest group influence) may explain the cross-national structure of average nominal levels of tariffs on manufactures. Using available data measuring or approximating the explanatory variables for the time periods 1902 and 1971, selected hypotheses were tested in regression equations. The 1971 tariff levels are best predicted by rational economic policy variables while for 1902, international power variables provide the best predictions of the tariff. In general, the causal forces influencing the cross-national pattern of tariff levels appear to have shifted in the 20th century from those indicating international power to those measuring domestic politico-economic development. These results provide evidence relevant to some of the general propositions about size and development suggested by the contemporary political economy literature. They also lend support to those who argue that a rising level of international interdependence has resulted in long-term changes in the pattern of influences on national public policies.