Poverty breeds violence. Then the police become fearful, over react and become violent, which leads to violence in response. It's a dangerous positive social feedback cycle. ("Positive" in the sense of a feedback cycle that moves a complex system further from stabilization. Another example is the melting of the Arctic ice and global warming. A negative feedback cycle, like a thermostat, stabilizes a system.)

Most of the poor and near poor -- the working class -- are white, and I think they are becoming more likely to explode also. There are other ways to kill people than using a weapon. A documentary on health care I watched said that the main determinant of health is income. The main reason is stress, caused by financial pressure. Stress sets people off. For example, when unemployment rises so does child and wife abuse. We need to do something about our economy. Either create more government jobs or set up a guaranteed annual income.