What about a state with a growth mindset? I feel it's a decent parallel to the behaviour of states as described by realism, or even to the Red Queen hypothesis where if you stop running you lose. https://en.wikipedia.org/wiki/Red_Queen_hypothesis
Growth for a nation has changed. 500 years ago there wasn't much ability for a state to grow except by expanding their borders. Your farmers couldn't produce enough food to feed more people (they would on a good year, but then the extra starve in a bad year), and so you could expand your economy only by growing your borders. Thus a noble (read rich) would build an army and go to war - this at best adds more land they control and thus more taxes, but even in the worst case destroyed a lot of people who then didn't eat freeing up more food for the rest. The limit was land not labor, so if you killed a lot of men (women were ignored) those left could work a little more and produce just as much food.
However starting 200-300 years ago the industrial revolution and various innovations have made other growth possible. Today war destroys far more than it gains you need a large industrial base to build a lot of equipment that you destroy (bombs are not cheap), plus all the equipment the enemy destroys. If you don't go to war you can instead use your industry to build more luxury goods (vacations are a valid luxury good for this discussion though we don't normally think of them that way!)
Note, war above is entirely from the attackers point of view, and it is - as attackers are - optimistic about the chances of winning a war. The defender has other considerations.
