My point is not to grieve for the victims and denounce the executioners. Those tears, that anger, cast into the past, deplete our moral energy for the present. And the lines are not always clear. In the long run, the oppressor is also a victim. In the short run (and so far, human history has consisted only of short runs), the victims, themselves desperate and tainted with the culture that oppresses them, turn on other victims.

— Howard Zinn, A People’s History of the United States