Some thoughts (prompted by discussion of the Finucane inquiry) that I believe are applicable to all sides in this and most other conflicts:-
We do not need to convince the "other side" that they are evil.
What we need, at its most basic, is for them not to want to attack or harm us.
It is very helpful if they come to believe that attacking or harming us is wrong.
If they come to believe this, it is actually helpful if they think of themselves as predominantly good people - it makes it more likely that they want to do the right thing.