Constituency Size and Responsiveness to Sectoral Interests: The Case of Japan and the Trans-Pacific Partnership

To build a political economy of trade, it is important to understand not only the demand for protection but also the supply of trade policy. The policy preferences of the public and special interest groups are filtered through political institutions creating winners and losers in trade policy formation. This article examines the impact of constituency size on the supply of trade protection. Although a number of political economy models make assumptions about the effect of constituency size on policy makers, recent studies testing the microfoundations of the theory have failed to find support for the claim that smaller constituencies produce higher levels of trade protection. It is argued that the main effect of constituency size is creating responsiveness to regional interests. It is found that electoral pressure from import-competing sectors drives policy makers from small constituencies' preferences toward the Trans-Pacific Partnership in Japan. Furthermore, legislators from small constituencies are more responsive to regional sectoral interests than legislators from large constituencies. These finding lend support for the constituency size hypothesis.