The goal of a war is to win Define "win". The goal of war is to gain or maintain power. Every war ever fought was to assert power. This does not necessarily

The goal of a war is to win Define "win". The goal of war is to gain or maintain power. Every war ever fought was to assert power. This does not necessarily require that those over whom you wish to assert power must die, but in reality most people prefer not to have someone else come in and tell them what to do, so they fight against the invader, thus requiring the death of those that oppose. Other armies will throw up a white flag and welcome the invaders in exchange for their lives, disproving your point that "the opposing army must die".