If you take for granted that a classic military force (threatening, and sometimes engaged in a war of aggression) is always necessary, then a way to suppress one of its mission is useless.

If you read some pretty authorized authors about it, let's say Smedley D. Butler ( https://en.wikipedia.org/wiki/War_Is_a_Racket ), then having one and only one mission for the army (self-defense) may be a better way.