"growing divide between America's armed forces and its civilian population."

"The social divisions of class and inequality have always run through the military. Fighting forces have long been drawn disproportionately from lower-income, lower-skilled, and more economically disadvantaged populations. But what is new, according to my colleague Patrick Adler at the Martin Prosperity Institute (MPI), is the degree to which those class divisions are underpinned by geography."

The map above, compiled by MPI's Zara Matheson, shows the concentration of military personnel across the 50 states.