The study examines the level of institutionalization in Korean party politics by focusing on individual legislators’ party switching as a micro-level indicator, in contrast to previous research that has primarily analyzed party-level mergers and spl...
The study examines the level of institutionalization in Korean party politics by focusing on individual legislators’ party switching as a micro-level indicator, in contrast to previous research that has primarily analyzed party-level mergers and splits. This approach rests on the assumption that instability in party politics cannot be separated into collective and individual dimensions, as transformations involving individuals, factions, and parties exist along a single continuum. Using data from the 17th to the 21st National Assembly, the study analyzes the trends, motivations, and timing of party switching. The level of party system institutionalization is evaluated according to Mainwaring and Scully’s (1995) criteria: stability of interparty competition, strong party-voter linkages, and organizational autonomy. Considering the characteristics of new democracies, this study expects party switching in South Korean National Assebly to occur frequently, to be motivated primarily by electoral survival and access to office rather than policy benefits, and to be concentrated in periods immediately preceding National Assembly elections.
The results show no consistent trend in party switching since the 17th National Assembly, with variation across assemblies largely shaped by major political events such as presidential impeachment and the emergence of new parties. Nevertheless, the overall frequency of party switching is exceptionally high compared to other democratic countries. At the same time, the proportion of switches between ruling and opposition parties remains relatively low, suggesting that despite frequent party mergers, splits, and label changes, the pattern of interparty competition has become stabilized. When analyzed by level, individual-level party switching remains notably consistent from the 17th through the 21st assemblies, whereas movements at the party and faction levels display strikingly similar patterns. This suggests that party formation and dissolution in Korea are deeply intertwined with factional dynamics. The findings indicate that although Korean parties may exert control over individual legislators’ movements, their fragmentation into multiple factions undermines their capacity to function as autonomous, unified organizations.
In order to identify the motivations behind party switching, this study first investigates its structural determinants through logistic regression analysis. The effects of legislators’ political resources, sociodemographic characteristics, and the regionalized structure of electoral competition on party switching decisions are examined. The findings show that ruling party membership, the regional location of the constituency, and the existence of a hegemonic party within the region significantly affect the probability of party switching. This suggests that legislators’ party choices are largely guided by considerations of access to political resources. Furthermore, although regionalism helps stabilize the pattern of interparty competition, it reinforces the salience of party labels over individual candidates, thereby increasing legislators’ responsiveness to structural changes at the party level.
Second, individual cases of party switching are categorized into six types according to their specific causes: changes in party reorganization, shifts in ideological orientation, conflicts with party leadership, corruption and scandals, electoral strategy, and other factors. The findings reveal that the trajectory of switching motivated by ideological shift closely resembles that of faction-level movements, indicating that positions on policies and issues are formed at the factional level and influence decisions to change party affiliation. This pattern implies that factions in Korea are not simply interest-based coalitions centered on reelection or access to office, but groups that cohere around shared principles or political tendencies.
Finally, the findings indicate that party switching occurs most intensively during the midterm periods between general and presidential elections. During this time, switches are primarily motivated by ideological shifts. By contrast, in the six months leading up to the next election, ideologically driven switching declines and switching prompted by party reorganization increases. This pattern underscores the connection between party reorganization considerations and legislators’ reelection motivations.
Taken together, these findings demonstrate that, despite the stability of interparty competition rooted in regional voting patterns, parties and voters in Korea remain only weakly linked through shared interests. Furthermore, political parties as organizations lack substantive autonomy and undergo reorganizations aimed at improving their public image as elections approach. In contrast, intra-party factions coalesce around shared ideological and policy positions but develop distinct programmatic differences from one another, generating continued fluidity in Korean party politics.