Like @TobinL said, you need to have everyone going into the game knowing that part of the dynamic is the negotiation, deceit, and betrayal. So long as you all know that (and nobody’s too upset when you “accidentally” send the troops across the border) it can be fun.
If ever wanted to take a crack at a board game and like more cooperative games, Carcassonne is really fun. I’ve won while applying a fully cooperative Satyagraha approach of never harming other people out while laying tiles down (and helping when it’s mutually beneficial). It is extra entertaining when you are beating people at a game while quoting Gandhi.
