If we allow us a couple of seconds of utopia, and believe human security's claim over the changing nature of boundaries hook, line, and sinker, then it is easy to understand who is getting out of the picture. Yes, in the ideal world without international rivalries, most of the problems derived from the dark side of human nature should be dealt by the police. No use for armies. In fact, we do not need to go as far as utopia, since the example of Costa Rica is there to remember that such a thing is possible.
That is why armies in the first world, when they are not planning preemptive attacks, they spend a good share of time trying to reinvent themselves. Recent examples could be, the offer to blow a solution up to the problem of the gulf, or the announcement of advances on a vaccine on Ebola.
Nonetheless, it is discouraging to find out that a glorious army is not good enough to protect itself - and its nuclear arsenal - from forest fires.
Maybe if we make rescue rangers of them...