Working Paper

Institute for Future Strategy

IFS Working Paper 2026-01 (Vol. 1)

Social Polarization and National Integration in South Korea

Subjective Perceptions of Political Moderation among South Korean Voters

Dong-Kyun Im (Professor, Department of Sociology, Seoul National University)

This study explores the internal criteria that shape how South Korean voters perceive themselves as politically moderate. Viewing political moderation as the cognitive product of multiple political attitudes, perceptions, and emotions, it analyzes data from the National Survey on Conflict Resolution and Social Integration in South Korea (N = 3,000) conducted by the Institute for Future Strategy at Seoul National University. The study operationalizes ideological self-placement on an 11-point scale using both a broad definition of moderation (scores of 4–6) and a narrow definition (score of 5). A total of 117 variables—including party and politician favorability, policy attitudes, political participation and efficacy, partisan hostility, institutional trust, and demographic characteristics—are analyzed using Gradient Boosting Machine, SHAP, partial dependence plots (PDP), and Elastic Net regularized regression, with predictive performance evaluated through nested cross-validation. The results show that subjective perceptions of political moderation are driven overwhelmingly by affective evaluations of political parties and politicians rather than by ideological or policy positions. Respondents who expressed favorable feelings toward any political party were less likely to identify as moderates, whereas strong dislike of parties did not distinguish them from respondents with neutral attitudes toward political parties. Moreover, when moderation is defined more narrowly, indicators of political disengagement—such as low political interest and uncertainty ("don't know") about opposing parties—emerge as the strongest predictors. These findings suggest that broadly defined moderates are best characterized as disaffected moderates, who distance themselves from major parties while holding negative feelings toward them, whereas narrowly defined moderates are better described as inattentive moderates, who are additionally disengaged from politics and lack partisan cognitive frameworks. The findings further suggest that fostering social integration in South Korea will require political actors capable of inspiring optimism and constructive political engagement among moderates rather than reinforcing political cynicism.

Keywords: political moderation, subjective ideological self-placement, affective polarization, machine learning, SHAP, political disengagement