It's the single largest category of spending, outside of medicare and social security, which are taxed and funded within their own category separate from regula

It's the single largest category of spending, outside of medicare and social security, which are taxed and funded within their own category separate from regular income taxes, and are "mandatory spending". Also note that Brookings tends to lean pro-military so 15% is likely an under-representation. If you remove mandatory spending it's more like 50%: https://prospect.org/economy/tax-dollars-really-go/ https://prospect.org/economy/tax-dollars-really-go/