Are you sure that stopping it will actually minimize the number of deaths in the long run? Is it better to kill 20000 people in a short time to reach permanent

Are you sure that stopping it will actually minimize the number of deaths in the long run? Is it better to kill 20000 people in a short time to reach permanent peace, or to save some of those people and then repeat the whole ordeal each 2 years, with more and more bloodshed? I don’t pretend to have an answer, but war brings up very hard to answer moral questions.