https://doi.org/10.1177/2233865918776849 International Area Studies Review 1–17 © The Author(s) 2018 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/2233865918776849 journals.sagepub.com/home/ias Social divisions, party support, and the changes in the Thai party system since 2001 Kai-Ping Huang Department of Political Science, National Taiwan University, Taiwan Stithorn Thananithichot Research and Development Office, King Prajadhipok’s Institute, Thailand Abstract This article investigates the interactions of socioeconomic characteristics and electoral outcomes at the constituency level to demonstrate the change in the Thai party system since 2001. Probing the effects of the agricultural population and income inequality on electoral outcomes in the proportional representation (PR) tier, this article finds that the Thai Rak Thai Party (TRT) and the Democrat Party (DP) attracted voters with opposite social standings. While voters residing in the provinces with substantial agrarian populations tended to vote more for the TRT than the DP, constituencies with highly unequal income distribution were more likely to be DP supporters. The findings provide evidence against alternative explanations, including regionalism and support for a charismatic leader, for the TRT’s consecutive victories. Due to the convergence between social divisions and party support, the Thai party system has become stable and strong enough to resist short-term interventions, implying that the future electoral outcomes will likely be similar. Keywords Social divisions, party support, agricultural population, income inequality, Thailand Introduction Division and polarized politics have defined Thailand in the past decade. The demise of the revered King Bhumibol Adulyadej in October 2016 added another layer of uncertainty to Thailand’s future. With two military coups and the latest constitution passed in 2016 that limits people’s rights and participation in politics and the power of elected governments (e.g. McCargo, 2015; Nelson, 2015), Corresponding author: Stithorn Thananithichot, King Prajadhipok’s Institute, Government Complex, Building B, Chaengwattana Rd., Laksi, Bangkok 10210, Thailand. Email: stithorn@kpi.ac.th 776849IAS 0 0 10.1177/2233865918776849International Area Studies ReviewHuang and Thananithichot research-article 2018 Article