What’s the origin of regionalism and what theory can explain the Korea’s regionalism?Because korean political party which is based on the regionalism nominate someone who is well connected with certain area as a candidate many citizens are under influence of regional feeling. Some people hate the other area person intentionally and they don’t want the candidate who is from another area elected. Regional feeling might be seemed as hatred toward the other area and attachment toward their hometown. It seems like that the psychological approach might be applied for the Korea’s election. But we have to think about the origin of regionalism deeply. If we look at the historical aspect, many former president promote regional feeling to extend their regime. They compensate for the people who live in certain area by developing their area. They construct the highway and industrial facility only in certain area. They could give some kind of expectation which their area will be more developed toward the area’s citizen. So Regionalism is based on the expected utility which is calculated by the electorate who consider their future advantage of their hometown and the possibility that they can advanced to the mainstream society. So regionalism is example of rational perspective. Regional voting is based on calaulation of expected utility