As they were during the Cold War, urban population centers remain the most likely targets of a nuclear attack. Now, however, an attack may come without warning from an unknown enemy, to achieve unclear motives.
Look for the enemies of Medicare, of higher minimum wages, of Social Security, of federal aid to education and there you will find the enemy of the Negro, the coalition of Dixiecrats and reactionary Republicans that seek to dominate the Congress.
It is the acid test of nonviolence that in a nonviolent conflict there is no rancor left behind, and in the end the enemies are converted into friends.