I've been meaning to suggest the book Prisoners of Hate: The congnitive basis of anger, hostility, and violence by Aaron T. Beck for some time now. If you click on the Barnes & Noble link above, you will be able to read some professional book reviews. I found it to be a convincing and engaging read -- though better in the diagnosis of problems than in their solution.
The scope of this book is vast and almost beyond summarizing -- finding a common thread between barroom brawls, domestic violence, terrorism and war. Along the way, it answers the question asked by so many -- why can't the people who hurt me see that I AM RIGHT AND THEY ARE WRONG?
Here is the table of contents for the book, which gives you a flavor of what Dr. Beck argues:
ch 1 The Prison of Hate: How Egosism and Ideology Hijack the Mind
ch 2 The Eye ("I") of the Storm: The Egocentric Bias
ch 3 From Hurt to Hate: The Vulnerable Self-image
ch 4 Let Me Count the Ways You've Wronged Me
ch 5 Primal Thinking: Cognitive Errors and Distortions
ch 6 Formula for Anger: Rights, Wrongs, and Retaliation
ch 7 Intimate Enemies: The Transformation of Love and Hate
ch 8 Individual Violence: The Psychology of the Offender
ch 9 Collective Illusions: Group Prejudice and Violence
ch 10 Persecution and Genocide: Creating Monsters and Demons
ch 11 Images and Misperceptions in War: The Deadly Construction of the ENEMY
ch 12 The Brighter Side of Human Nature: Attachment, Altruism, and Cooperation
ch 13 Cognitive Therapy for Individuals and Groups
ch 14 Perspectives and Prospects: Applying Cognitive Approaches to the Problems of Society
The chapters dealing with war and genocide warn that assuming that all of the good is vested in your group and that all of the evil is vested in the other side only leads to tradegy. He doesn't pretend that people never mean harm, only that retaliation will never lead to peace, but will only strengthen BOTH SIDES feelings that they are ABSOLUTELY right and the other side is ABSOLUTELY wrong. They will then redouble their efforts to eliminate the hopeless evil other.
As we gaze across the globe, this message seems true to me. It's put into the terms of cognitive psychology, but it represents thought I believe that Christ and Gandhi would have recognized and endorsed. It's worth a read.