The Warring States Annals, or The Chronicles of the Warring States, it was a history book.
The topic was, you guessed it, the Warring States period.
That is how we know about the Warring States period, because of this history book.
But this is not just a history book. We have to remember that back in those days, books like this were written by the best minds there were among Chinese people.
This is a book of literature too. This was a book of short stories, very short indeed. These stories got right to the point, good literary style, and a lesson in there somewhere.
So when someone says this is straight out of the Warring States period, that means this is a story straight out of that book.
And that book was full of stories of political events, moral codes, intrigue, plots, and brutality. It was a great work!
Now for the specific story regarding the predicament that Australia finds itself in today, which was brought up by the poster who originally mention it, got to ask them which story was they thinking about from the Zhan Guo Ce. I don't remember, all I remember was a couple of stories. Not even sure if it was from there or some other ancient book, lol.