Justification for war and all the debate on the subject goes back to the Romans with essays as Catiline Orations and Philippics by Cicero. The subject started to be an issue in times of Julius Caesar, when decisions on warfare where monopolized by the future emperor. In fact, polemics escalated until the point that Rome stopped to be a republic to become an empire.
Justice is a universal value for humans; our society holds tightly the idea of carrying it as a slogan for progress. The value is in our consciousness and we listen to people talking about it in morning television shows. I personally think that justice is the card that people play when they catch kids stealing Mars Bars from the drug store, mainly because they don’t have the guts for stealing them themselves. This concept is doubtlessly complicated and many people squinted when the subject was brought in the plaza in the old days. I can see Cicero squinting his ass off when Caesar started to talk about his outlandish sense of justice. World leaders have had different ways of putting justice in the table – and it makes sense because justice, morality, and many other non-tangible concepts don’t really exist, it was a concept made out of greed utilized against fast thinkers when they started cheating in card games and in “find the ball in the tree cups” in La vieja España – you can define justice the way you like, really I’ll be alright. So, what is really important about justice is perhaps not the concept itself but whom we think the pertinent authority is to say what is really just and what is not.
Throughout the eras, the right of saying what is just has been only granted to a limited extent of people. This means that only certain individuals could really grasp the knowledge of what is just and what is not, the possibility for a civilization to engage war with another also rested on these people’s shoulders. Civilians didn’t really have the knowledge of what is just or not, nor a word on private matters.