This paper strives to examine if and how an actor can achieve success. With the help of Jomini´s theory about positions and defensive battle. This study wanted to enlighten the problem that science have had focus substantially on that only through offensive approach an actor can achieve victory. No science is explaining its possible to win through an defensive approach. This study can strives to enlighten that an army can achieve success despite an defensive approach. This research analysis two cases from the Korean War, the battle of Kum River and the first battle of Naktong Bulge in 1950 and the analysis is on how the American 24 infantry division acted during these battles. The result shows that Jomini´s theory can explain the outcome in these battles. But there is more factors that needs to be taken into account to understand the whole spectrum of the outcome in defensive battles.