Legitimate warfighting is where sensible pacifist civilians have a sufficient notice and a chance to leave the intended warzone with their belongings before the war starts. It is also where military, industrial, and infrastructural targets are the only targets, where reasonable efforts are made to avoid targeting civilians. Legitimate warfighting brings freedom in the end, whereas illegitimate warfighting takes it away.
What percentage of wars are fought with the intention to bring freedom in the end? A lot of wars are just the result of imperialism. I think that definition is somewhat artificial.
