Take a look at this map of peace across the states. The higher its score, the less peaceful it is. Inequality, violence, poverty, low educational attainment, and lack of social capital contribute to the score. 

(Source: theatlanticcities.com)

Take a look at this chart comparing death rates for young people in the rich world.

The rate of violent death for American youth is 18 TIMES HIGHER than for British youth. 

(Source: economist.com)