If the criteria for International politics is different from that of 'local' politics, how do we reconcile the two?

If the political International scene is governed by a different criteria from that of the local or National scene, how do we reconcile the two levels? Surely, an 'individuals life' on the National scene is as sacred as an 'individuals life' on the International scene. But here is where we make the transition from 'National' rules to 'International' rules of government. At this point, we must be very careful. Surely, 'life' on the International scene is just as sacred as it is ,or should be, on the National scene. But, not all governments are democratic. So, do we have a right to interfere with other ways of life because of their 'local' abuses or cruelty towards their members of the polity? I mean, how do we protect 'human life' on the International scene by a criteria that should relate to peaceful International relations? Of course, it would be ideal if the whole International scene respected individual life as some National governments do. Even then, no political entity is perfect. Normally, the answer would be No, we do not have a right to interfere, unless it will encourage others to assume the same lackadaisical attitude towards human life. If previous International 'policy' has seen fit to 'draw a red line' against the use of chemical 'weapons', that red line should be respected by all parties. If that International policy is intentionally violated, what can the National level do? The violation must be 'clear' and unquestionable. But, having established that clarity, the only answer is to respond. The question becomes, by following the rules of International politics and International inquiry, has that clarity been established as an International fact? If so, and if the International Nations have previously drawn that 'red line', unfortunately, there is no choice in the matter.