Abstract This paper formulates a mathematical model that combines the dynamics of interest group formation with electoral politics, involving office-seeking and corrupt political candidates and voting population with well-defined policy as well as ideological preferences. The analysis provides several interesting insights into the factors affecting lobby membership, free-riding incentives of citizen-voters and aggregate monetary donations garnered by lobby groups. Besides this, the paper also explores the impact of the formation of distinct lobby groups, the presence of swing voters and the corrupt practices or financial embezzlement on the equilibrium policy choice of electoral contenders. The findings reveal that more honest spending of campaign donations by electoral contenders reduces both the size of the lobby (or membership) as well as aggregate campaign contributions in equilibrium. In contrast, a rise in the fixed cost of organization is found to augment lobby membership along with the total amount of campaign contributions. In addition, a reduction in the level of electoral uncertainty as well as a rise in the ideological or swing voter density is found to increase the effectiveness of campaign contributions in raising an electoral candidate’s perceived popularity and, therefore, a smaller lobby group with lower aggregate donations is deemed as sufficient in influencing electoral outcomes. Moreover, the results indicate that a lower utility difference derived by the citizen-voters when comparing the two electoral candidate’s policy choices translates into smaller dispersion of the voters’ ideological bias, and consequently results in an increase in the size of lobby groups and their corresponding aggregate donations. As regards the choice of equilibrium policy, evidence of full policy convergence is not found in the case when citizen-voters of the two groups have separable preferences. In addition, policy equilibrium for a more realistic case in which the two policy platforms exhibit strategic interaction by reacting to each other has also been estimated with the help of simulations. Finally, this paper helps in categorically deciphering the influence of the median voter effect (or the centripetal force) and the distinct centrifugal forces in the form of lobbying effect, swing voter effect and the financial embezzlement effect on the equilibrium policy choice by employing different parametric specifications of the model.

中文翻译：

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检查选举竞争和内生游说形成对均衡政策平台的影响

摘要 本文构建了一个数学模型，将利益集团形成的动态与选举政治相结合，涉及寻求办公室和腐败的政治候选人以及具有明确政策和意识形态偏好的投票人口。该分析对影响游说成员的因素、公民选民的搭便车激励以及游说团体获得的总捐款提供了一些有趣的见解。除此之外，本文还探讨了不同游说团体的形成、摇摆选民的存在以及腐败行为或财务挪用对选举竞争者均衡政策选择的影响。调查结果表明，选举竞争者更诚实地花费竞选捐款会减少游说团（或会员）的规模以及均衡的竞选捐款总额。相反，发现组织固定成本的增加会增加游说成员的数量以及竞选捐款的总额。此外，选举不确定性水平的降低以及意识形态或摇摆选民密度的增加被发现可以提高竞选捐款在提高选举候选人的受欢迎程度方面的有效性，因此，较小的游说团体具有较低的总人数捐款被认为足以影响选举结果。而且，结果表明，在比较两位候选人的政策选择时，公民选民的效用差异较小，这会转化为选民意识形态偏见的较小分散，从而导致游说团体的规模及其相应的总捐款增加. 关于均衡政策的选择，在两个群体的公民选民具有可分离的偏好的情况下，没有发现完全政策趋同的证据。此外，在模拟的帮助下，还估计了两个政策平台通过相互反应表现出战略互动的更现实情况的政策平衡。最后，