I imagine that these kinds of issues come up a lot in other federal systems. Not all decisions are made at the national level, with significant decisions made at the local or state level. Hell, a lot of federal agencies' jobs is to be a resource for states, in both budget and technical expertise.
States in the United States have a lot of the competencies that nations in the EU do, including state run militaries. It is just usually hard for a lot of non-Americans to understand how much power is given away.