Right of conquest

It seems a fundamental paradigm split is over the right of conquest. This was unquestioned basically between nations until WWI but it is also univ ersally prohibited among members of a society. Assault and theft ( "mugging") is against every social code binding all communities i have heard of. evn groups that prey on others violation within the social group is prohibited. What do we accept this so easily? If a nation has the right to use force why not an individual? Could it be the true Original Sin; ethnocentrism/tribalism/racism? Violence is allowed if it is against the outsiders. Or could that be an adaptation to allow the group to survive? if that is the case humans evolve in groups which is quite a bit different than our self image but easily observable in other organisms. The Left has issues with conquest and power. the right is all about power and grouip solidarity, holding Universality to be a lie used by totalitarian utopians ( as all utopians must be according to conservatives.) The true issue in the Middle east is rights of conquest, both by the Muslims in the 7th and 8th centuries, the Israelis both in ancient times and in the 20th century. The formation of nation states out of the provinces has been bloody. History does matter.