Between Ideology, Strategy, and Polarization: Understanding Judicial Decision-Making Amid Court-Packing

In recent decades, democratically elected governments have increasingly sought to curtail the power and independence of higher courts through a range of court-curbing strategies. Court-curbing encompasses both formal and informal actions aimed at weakening judicial authority, including court-packing, non-compliance with judicial decisions, and public attacks on judges. Among these tools, court-packing—defined as reforms that alter the size, composition, or appointment rules of constitutional courts—has emerged as one of the most frequently employed strategies by incumbent governments seeking to undermine judicial independence. Despite a growing body of scholarship examining court-packing reforms in countries such as Poland, Hungary, and Turkey, existing studies struggle to disentangle whether observed changes in judicial behaviour result from institutional reforms themselves or from the broader political transformations that motivate these reforms. Endogeneity thus remains a central challenge in assessing the causal impact of court-packing on judicial decision-making. This study addresses this gap by developing a multidimensional framework to explain whether, how, and through which mechanisms court-packing practices influence the behaviour of constitutional court judges. We conceptualize court-packing not as a one-time institutional intervention but as a dynamic process that operates through three distinct mechanisms. First, court-packing enables governments to appoint partisan judges, directly shifting the ideological composition of the court. Second, court-packing generates a signalling effect by demonstrating the strength and resolve of the incumbent government, thereby shaping judges’ strategic behaviour in anticipation of political retaliation or support. Third, court-packing alters intra-court dynamics by increasing polarization within the court, which in turn affects deliberation, coalition-building, and decision making. These mechanisms operate across three analytical levels—the judge level (individual ideological preferences), the court level (intra-court polarization), and the political context level (governmental power consolidation)—and interact to shape judicial outcomes. We empirically test this framework using an original dataset of all Turkish Constitutional Court (TCC) constitutional review decisions issued between 2002 and 2024. The dataset includes 8,147 cases and 135 judges, with the judge-article vote serving as the unit of analysis. Focusing on judicial behaviour under the rule of the Justice and Development Party (AKP), Turkey offers a particularly suitable case given the AKP’s sustained consolidation of power and its extensive use of both formal and informal court-packing strategies, especially following the 2010 constitutional amendments and the post-2016 purge of the judiciary. Our findings demonstrate that court-packing reforms affect judicial behaviour through multiple, interacting channels. While ideological alignment between judges and the incumbent government remains an important determinant of judicial decisions, both the broader political context and intra-court polarization significantly condition the expression of judicial ideology. Judges exhibit strategic behaviour in response to heightened political pressure and changing court dynamics, suggesting that neither purely attitudinal nor purely strategic models alone can fully account for judicial behaviour under court-curbing pressures. By opening the “black box” of constitutional courts, this study provides new causal leverage on how institutional reforms and political context jointly shape judicial decision-making in regimes experiencing democratic backsliding.