This study shows that intra-party competition shapes campaign messages well before candidates enter office. Analyzing 1,394 campaign brochures from South Korea’s multi-member districts, I develop a supervised text measure of particularistic appeals and test how they vary with co-partisan rivalry. Candidates facing more same-party competitors consistently emphasize narrower, targeted benefits. The commonly used C:E measure, however, performs poorly because nominations respond more to short-term electoral sentiment than to expected seat counts. These findings demonstrate how measurement choices reshape inferences about personal-vote strategies and highlight the value of integrating text analysis with qualitative evidence. 

This study examines how single non-transferable voting (SNTV), one of the most candidate-centered electoral systems, shapes legislative corruption. Using data on South Korean local councils (2013–2023) and a causal forest approach, I show that higher intra-party competition within districts is associated with significantly greater corruption. These findings underscore the importance of electoral system design and reveal how intra-party rivalry can exacerbate governance failures.