WHY DOES A TWO-PARTY SYSTEM EXIST?: A NEW ECONOMIC EXPLANATION*

The purpose of this paper is to present a new economic explanation for why a multiple-party system can endogenously arise as a result of the electoral process. The traditional view on the electoral process (i.e., the median voter theorem) is that political parties that pursue policies in the interest of the median voter are led to a convergence of policies. However, this view cannot explain why either conservative or liberal parties win election in many democratic countries. In order to explain this paradox, the following model considers an economy with three types of parties: conservative, middle, and liberal parties. In the model, the policy of each party is assumed to be time-consistent, so that the policy of the middle party generally leads to suboptimal outcomes for the majority voters. Thus, the “rational” majority voters try to elect the political party whose objective is biased. As a result, the electoral process may lead to a two-party system where both conservative and liberal parties have a chance to win election.     

A sensitivity analysis on optimal economic growth

A model of capital accumulation is considered and the relation between the optimal path and the initial capital stock is analyzed. Mathematically speaking, the model is a convex model of infinite horizon in continuous time. The existence of optimal paths of capital accumulation is proved. By using the continuity of the value function, it is proved that the optimal path of capital accumulation is a continuous function of the initial capital stock. The analysis is so general that neither the smoothness of the model nor the interiority of the optimal path are made.     

Market Valuation and the q Theory of Investment

This study re-evaluates the role of the stock market in Japanese corporate investment decisions based on time-series data. Employing the time-series technique, we examine why the performance of Tobin's average q -type investment function is poor. We construct a series of average q and another of marginal q (a more fundamental profitability measure of investment) and investigate the relationship between the two. A cointegrating relationship is not detected between the two measures, both of which have a unit root. The divergence of average q from marginal q is not narrowed even if the imperfect competition of the output market is taken into consideration. We also examine which q measure is more relevant to Japanese corporate investment decisions by estimating separately the investment function with two measures of q as an explanatory variable. The estimation results show that entrepreneurs place more emphasis on marginal q than on average q in investment decisions.
JEL Classification Number: E22.