>>1
All or several of the above, depending on what the situation calls for. An automatic, all-encompassing response ignores the complexity and shades of each situation.
"Evil," like any word, is in the eye of the beholder; to us, there is "evil," but it is not the same evil as it may be in other cultures, or simply in other people's minds. Because of this, we must be mindful of how we approach international situations/wars/crisis; to call someone, a regime, or a country "evil" would be to invite a response that lacks thought, and would therefore be potentially more damaging that the supposed "evil" we sought to eradicate/stop/etc.
tl;dr ignorance is the true evil