^ IA. Violence just begets more violence, fear more fear. What brings about change is a change in tactics, not responding in kind to perceived or actual injustice.
Let's take this down to a personal level. Someone starts screaming at you, raging at some supposed failing on your part. You can scream back. You can escalate the argument to violence. You can, through your actions and words, change the tone to one conducive to more civil resolution of your differences.
It's quite normal to lash out defensively, and sometimes needed if you're actually being physically threatened. But I can't think of a single time when I've succumbed to that temptation that it solved anything. Halted for the time being, maybe, but not solved. The only times I've been successful at bringing about change is when I've chosen the third option above.
The same holds true on the macro level, in countries and communities.
In my mind our response to 9/11 was a perfect example of doing all the wrong things albeit for understandable reasons. Rather than overwhelming terrorists with force or intimidating them with fear, we simply fanned their flames, added thousands of new recruits to their ranks, and essentially became who they'd been claiming we were to justify their initial attacks.
We could have chosen to lead by example, rallying a sympathetic world to hunt down only the specific individuals responsible for planning those attacks while condemning violence and demonstrating non-violent acts rather than invading countries.
But we didn't, and thus generations to come will experience the results.
Sadly, such is human nature, it seems.