District Medians and Median Districts: Electoral Adaptation in Post 1994 Japan

Abstract

There is considerable evidence supporting the prediction of spatial models of politics that parties adapt to electoral rules. But as in economic markets, adaptation can occur either when parties behave strategically in the face of new incentives, or when electoral competition at the district level weeds out maladapted candidates, creating more optimal party configurations from the bottom up. Although both processes can happen simultaneously, top-down strategic adaptation is easier when districts occupied by party incumbents are internally heterogeneous with respect to voter preferences and the range of preferences is similar across districts. Conversely, parties are hard to manage when their districts are internally homogeneous but different from one another. Following electoral rule change in 1994, an incumbency cartel within the long-dominant Liberal Democratic Party slowed down but did not stop the Party’s move to the national median. Electoral competition is apparently pushing both parties towards a left-right continuum as they orient themselves around urban swing districts. This adaptation gives business cycles a larger role in Japanese electoral politics than ever before.