South East Asia Research, 18, 4, pp 635–674 doi: 10.5367/sear.2010.0016 When parties swing: Islamist parties and institutional moderation in Malaysia and Indonesia Julie Chernov Hwang Abstract: This article examines the extent to which the Malaysian Islamic Party (PAS) and the Prosperous Justice Party (PKS) are becoming more moderate in their strategy and ideology. The au- thor contends that both parties are struggling over the extent to which they should moderate in response both to strategic incen- tives present in the Malaysian and Indonesian political systems and to the political learning process whereby both parties are coming to understand the preferences of voters in their respective political systems. This process is complicated by divisions in the parties be- tween pragmatists who would postpone controversial goals to reach out to non-devout voters, and purists who prioritize ideological au- thenticity. Keywords: moderation; strategic incentives; Islamist parties; PAS; PKS Author details: Julie Chernov Hwang is Assistant Professor in the De- partment of Political Science and International Relations, Goucher College, 1021 Dulaney Valley Road, Baltimore, MD 21204, USA. E- mail: jchwang@goucher.edu. In February 2008, the Partai Keadilan Sejahtera [Prosperous Justice Party – PKS] held its annual meeting in Bali and announced that it would open the party to non-Muslim members. To that end, it was revising its platform and its party documents to reflect this decision. Similarly, in March 2008, the Partai Islam se-Malaysia [Malaysian Islamic Party – PAS] released its manifesto in time for parliamentary elections. In it, I am grateful to Greg Fealy and Joseph Liow for their comments on an earlier draft of this paper, to the two anonymous reviewers for South East Asia Research and to my research assistant, A’an Suryana. I would also like to thank those who attended the APSA panel in Boston, 28–31 August 2008, where this paper was initially presented.