Nomination Strategies under the Single Non-transferable Vote System

Abstract

Parties need to optimize the number of candidates and allocate votes among them appropriately to maximize their seats under the single non-transferable vote system, which has been utilized in Japan for a long time. Existing studies classified the failure of this strategy by the relationship between the optimal and actual number of candidates. This classification, however, does not coincide with the classification by the two causes of the failure, i.e., the failure to equalize the vote and the failure of the excessive vote splitting. This study proposes the new classification by these two causes and applies it to the House of Representatives elections in Japan to examine the strategy of the long-ruling Liberal Democratic Party. The results suggest that the failure decreases over time not because the strategy has improved but because the electoral circumstances easy to avoid the failure have increased.