Why Do Legislators Switch Their Policy Positions in Trade Policies?: The Case of South Korea

ABSTRACT This study examines why legislators change their positions on Free Trade Agreement (FTA) ratification votes in the South Korean National Assembly, analyzing 17 FTA ratifications from the 16th to 20th Assembly. Using logistic regression with change‐based variables, I find that transitions in ruling party status, changes in party loyalty, and shifts in constituency economic composition significantly influence position changes. Directional analysis reveals asymmetric patterns: legislators who gain ruling party status are more likely to switch from opposition to support, while switches from support to opposition are primarily driven by increases in district manufacturing employment. Increases in agricultural employment are associated with switches toward support rather than opposition, possibly reflecting government compensation mechanisms. Interaction analysis shows that declining electoral security amplifies responsiveness to constituency economic changes, and that former ruling party members with high party loyalty are particularly prone to switching toward support. These findings demonstrate that legislative position changes in trade policy are shaped more by transitions in political context than by static characteristics, and that different types of position switches operate through fundamentally different mechanisms.