Ideally yes, even though humans have differing beliefs, there are ethics that reduce to facts about the human conscience experience. We can make certain statements about the well being of conscious creatures. For example, there isn't one right food to eat, but there is a clear distinction between food and poison. Who are we to pretend that we know so little about human well being that we have to be non judgmental. There are many ways to maximize the growth of humanity. Despite differing beliefs, we can generally agree that adding cholera to a water supply is detrimental to human flourishing. We can ask ourselves if subjecting children to violence and public humiliation encourages healthy emotional development. I'm not talking about the voluntary wearing of whatever clothing, but what are the chances that a girl being murdered because she was raped represents a peak of human development. We have to admit that there are right and wrong answers about human flourishing and what leads to unnecessary human suffering.
War usually happens when all diplomatic negotiations are useless. Accordingly, trying to enforce a single set of ethics during war would be an impossible and hopeless task. Moreover, the concept of "ethical" war is an oxymoron. War is murder, and there is no euphemism that could make war a more tolerable concept.
While it would be wonderful if we could eliminate war from our world, all of our countries have very different belief systems that simply cannot be held to the same ethical structure. Ethics very by belief system and picking one specific system would negate what other countries believe. Allowing everyone to have different beliefs in this world is very important.
No, not all countries should operate under the same ethics of war, because it would be impossible to enforce something like that. The honest countries would follow it, and the dishonest countries would either hide behind political subgroups, or they would just ignore the ethics rules anyways. You can't police ethics
No, not all countries should operate under the same ethics of war, because it would be impossible to enforce something like that. The honest countries would follow it, and the dishonest countries would either hide behind political subgroups, or they would just ignore the ethics rules anyways. You can't police ethics.