It's not the military! America is extremely inefficient/bureaucratic in various mainline institutions. Military is %5 of GDP, health care is %17/%18 of GDP. A typical socialized medicine country like finland or canada pays about %11 of GDP for healthcare. If the USA brought health care to match socialized medicine costs, it would pay for the military plus more. Pretty much the majority of the USA's federal budget goes towards social security, medicare and medicaid.

Even though the USA pays the most in the world for it's military, I was surprised how little of the GDP it actually was.