I've been reading a lot of history lately and it seems that the only way someone wins against guerilla fighters is through genocidal or extremely destructive means. The guerillas always seem to have like a 1:2 KD ratio. Has there been any effective campaign?
Yes! In modern counterinsurgency, there are some great examples and guidelines which have been proven to work. I've compiled some of them in this thread where I also use specific examples from specific conflicts.
If you have any more specific questions, feel free to ask!