中文摘要
政策制定涉及政策对不断变化的情势作出响应与保持政策稳定之间的权衡。然而，人们对于代议制民主如何处理这一权衡知之甚少。轶事证据表明，政策不仅未能对情势变化作出有效响应，而且还会随着政治更替发生不必要的变化。我们在一个动态选举模型中研究这一权衡：模型包含一名选民和两个意识形态不同的政党，所有参与者都因政策从一期到下一期发生变化而承担一项共同成本。选举前，选民会观察当前政策，以及一个关于其下一期政策偏好的信号。我们证明，与经验证据一致，自由派（保守派）在任者在实施自由派（保守派）政策后更有可能连任。由于预期到这种选举偏向，在任者对状态的响应程度降低，转而使政策制定向自身的意识形态倾斜。因此，与不存在选举压力的情形相比，政策对真实冲击的响应不足，而对政治更替的响应过度。我们研究了由此产生的低效率如何随稳定性偏好、选民信息、意识形态极化程度以及政党的执政动机而变化。
Abstract
Policy making involves a trade-off between policy responsiveness to changing circumstances and policy stability. Little is known, however, about how this trade-off is resolved in representative democracies. Anecdotal evidence suggests that policies not only fail to respond efficiently to changing circumstances but also change unnecessarily with political turnover. We study this trade-off in a dynamic election model with a voter and two parties with distinct ideologies in which all players incur a common cost for changing the policy from one period to the next. Before elections, the voter observes the current policy as well as a signal about her policy preference for the next period. We show that, consistent with empirical evidence, a liberal (conservative) incumbent is more likely to be reelected after having implemented a liberal (conservative) policy. Expecting this electoral bias, the incumbent is less responsive to the state and instead tilts policy making towards its ideology. Hence, as compared to a world without electoral pressures, policies under-respond to real shocks and over-respond to political turnover. We study how the resulting inefficiencies vary with preference for stability, voter’s information, ideological polarization, and office motivation of the parties.