Regionalism is a key variable in analyzing Korean election results. A dominant support for and a landslide victory by a certain party in a given region have been common phenomena in almost all elections since the country’s democratization in 1987.This study argues that the dominant effect of regionalism in voting behavior has been debilitated in spite of its apparent solidity. Specifically, this study differentiates Yeongnam, which previously have been classified as one region, into two sub-regions, Daegu/Gyeongbuk(TK) and Busan/Ulsan/Gyeongnam(PK) and investigates the ;;regional cleavage’ between them. In order to examine the pattern of these changes in regionalism, this study aims to look at both the election results and public opinion in TK and PK region through empirical election data and regional newspapers editorials in TK(Maeil-Sinmun) and PK(Busan-Ilbo). In the 1992 general election, the average percentage of votes for Saenuri-Party-Affiliates(SPA) candidates in the PK region was higher than that of TK. However, in the 2004 and 2016 general elections, the share was higher in the TK region. In proportional representation elections, SPA showed the similar trend as well. Both TK and PK regions are known for their almost unanimous support for SPA. However, it is clear that electorates in TK and PK has been demonstrating different voting behaviors even before the 2016 general election.In the course of the three elections, regional newspapers presented increasing interests and concerns on local issues, especially on the local economy. It has also become clear that TK and PK, which were once a single unit, are now competing each other to attract facilities and institutions to boost their disparate regional economies. The competition for accommodating the new southeast airport is a good example of this rivalry. This schism in Yeongnam Regionalism has gradually developed since democratization in 1987. After the 1987 presidential election and the 1988 general election, the complaints and criticisms of Yeongnam voters on Kim Daejung increased. This was because Kim Daejung created a new party just before the presidential election, and his political move resulted in a failure of agreement on a single presidential candidate between him and Kim Youngsam. In addition, because of ;;Three-Party-Mergence” in 1990, Honam area was locally and politically isolated. The negative image of Kim Dae-jung was directly related to how Honam was perceived among voters, especially in Yeongnam region. As a result, Honam became a distinct out-group of Yeongnam, and the identity of Yeongnam as the in-group was established.In 2002 presidential election, Roh Moo-hyun, who was from PK, was elected as the presidential candidate for a political party supported by Honam. Roh, who had been trying to defeat the regionalism, had gained greater support in PK region compared to Kim Daejung in 1997 election. Political reforms of Roh administration increased satisfaction of voters on democracy and the political agenda. The Balanced National Development Policy was one of such reforms. Due to this policy, regional governments began to compete each other to earn more economic resources from the central government.As a result of these changes, Yeongnam split into two sub-regions, and the electorates began to form different senses of identity from the new in-groups based on the sub-regions. At the same time, PK electorates began to seriously consider non-SPA party and its candidates as their alternative political representatives. TK electorates and PK electorates show significant group differences in their political awareness. An increasing number of electorates in PK are expressing their support for the candidates of non-SPA. As a result, PK electorates are ;;breaking away’ from Yeongnam, the former mono-political unit.