AI self destructs

[jaif]

In my game one of my neighbors was banderlog, but it appears that their empire was destroyed by independants. My spy in their capital shows me an independant force besieging their capital. Meanwhile, their dominion was horrible - misfortune, death, turmoil, drain, and the other one all at 2 or 3.

Is this some fancy strategy thing? Can someone explain what's happening? With them out of the way it was easy for me to expand, which makes this game trivial to win.

-Jeff