My first Post:
I'm a new (very new) player. I learned that war isn't really a thing in this game in any conventional sense, because it would be too hard to implement. I know a simple, free, no-sign-up strategy game called Antiyoy Online that can be downloaded on the play store. It is made by a programmer named Yiotro. He has a few games, but I feel that this one would fit best with NationStates. Once you see the rules of the game, how simple the interface is, and the fact that it is completely free and has no ads, you might find you enjoy it. I propose that if two people want to go to war, they can (optionally, of course, they choose to go to war however they want) set up a Custom Online Match. Once you understand the game, you'll see how easy it is to generate a random 2-player map without AI, no diplomacy, and fog-of-war.
And no, I am not endorsed by nor work with Yiotro, I just think his game (Antiyoy) is cool.