I believe that means sustaining within normal expenditures, in a major conflict the whole economy would be enlisted towards the effortI keep seeing "analysts" saying that the US cannot sustain operations for more than a week or two. If that were true the US is screwed. Any conflict with China would require 10x the expenditure this does.
No wonder that you can't afford coffee. It isn't Trump's fault that Granger is gouging on their coffee price.