What Then Must We Do?

Not a hypothetical quiz. This is the reality we are in and on the verge of entering.
What is the best, final resolution? for those who transgress acceptable social normative behavior, for whatever reasons, either within a nation state or in the name of a sovereign state:
1) Kill them all even that means genocide, the perpetrators as well as those who were merely there, complicit and openly objecting.
2) Take the time and effort in the name of some kind of justice to separate out the openly objecting from the rest and then commit genocide.
3) Kill everyone on both sides as the ultimate simplification of resolving the conflict.
4) Capture and incarcerate the perpetrators of injustice as judiciously as possible with as little restriction on their freedoms as possible while providing protection of everyone else from their antisocial behavior, placing no blame on them for what they did.
5) Make a desert of the entire region and call it “peace.”
Your alterative propositions welcome. This is an open discussion. If you need a specific context to help focus your responses, let’s take Israel and Gaza. Please make explicit on whom you would apply your solution.
But I am open to any and all times and places. I want this to be a broad discussion of how we humans should practically handle our conflicts and behavior which are outside civil norms much of our world has become accustomed to.