Why do extremist or anti-system parties follow different paths in their ideological transformation? This study assesses the explanatory power of party change theories by comparing two anti-system parties from Turkey. Indeed, the ideological transformation of the pro-Islamist and the ethnonationalist Kurdish parties ended up with divergent fates in Turkey: The pro-Islamist parties (1970-2002) followed the path to moderation, incorporating into the center-of-the-system through the emergence of the AKP in 2002, whereas the pro-Kurdish parties (1990-2015), despite a deviation from an ethnonationalist discourse in 2013, continued to distance themselves from the center. This paper argues that while the electoral imperative generates a more encompassing ideology for both parties, the divergence of paths in ideological transformation is mainly explained by the nature of state-party interaction: If the level of state repression is higher, the anti-system party chooses to remain distant from the center-of-the-system. In this way, this study aims to contribute to the understanding of reasons for the unequal treatment of anti-system/extremist parties compared to mainstream parties in a democratic system.
