Electoral origins of Japanese socialists' stagnation

Why did the Japan Socialist Party (JSP) cling to its original leftist policies for so long? Traditionally, the JSP's failure to become a credible alternative to the Liberal Democratic Party (LDP) has been explained in terms of either the legacy of its disastrous coalition experience in the early postwar years, the party's organizational reliance on unionized labor, or its nervousness about the reactionary element in the LDP. None of these existing explanations is convincing, given that the adherence to its leftist policies had self-defeating electoral consequences for the JSP. This article explores an alternative explanation and provides empirical evidence which illustrates the link between the JSP's misfortune and the Japanese electoral system existing from 1947 to 1994.