Exciting history book exploring, in detail, governing bodies managing their nations and war through the lens of realpolitik

Been watching legends of the galactic heroes and really like watching the government bodies dispute amongst themselves. It was very realistic. Then I learned it's because it's an adaption of European wars, just like asoiaf was based on war of roses.

So I'd like to read a history book thats exciting like those, focusing on government bodies inner circle and their logic of managing their people and outside conflicts. Ideally not on European War or war of roses because I'd like something different. I read I, Claudius and that was a fun read, albeit was focused more on family than governing difficulties/debates. suggestions?

Thanks in advance.