There's a growing gap between American civilians and the military. Since the US ended the draft, the percentage of Americans who serve has declined. This time-lapse map of the percent of young Americans who are veterans does a great job illustrating this trend.
MetricMaps used data from the 1980, 1990, and 2000 US Censuses, and more recent American Community Survey data from 2009-2013, to determine the percent of Americans aged 18-34 who were veterans as of those years. This GIF shows what they found — a clear and steady decline in the percentage of young veterans around the country:
The really telling thing about this map is that the Iraq and Afghanistan wars interrupted but did not reverse the trend. Despite the fact that the US saw much more war in the 2000s that it did in the 1990s, the percent of civilians who were veterans kept falling. War is increasingly being outsourced to a smaller minority. And that minority is carrying a very heavy burden.
This has implications for America's role in the world. For one thing, the American public is less attuned to wars once they start, leading to weak public interest in and oversight over ongoing wars. "With these post-9/11 wars, which are now past the 10-year mark, the public has been paying less and less attention," Paul Taylor, executive vice president of the Pew Research Center, told the New York Times.
The Times' Sabrina Tavernise also suggests this could hurt relations between the military and the civilians who command them, as the military becomes increasingly isolated and culturally distinct from the rest of the nation. But, despite widespread belief to the contrary, the fact that the military is increasingly volunteer probably does not make the US more willing to enter wars: historically, drafts don't actually deter presidents from getting the US into conflicts