One of my favorite dynamics: Warrior class that really kicks butt, takes control over the state and then slowly becomes obsolete but is so embedded in the social structure that it just sticks around sucking up vast resources for hundreds of years. I've read the Ottoman Empire had this happen with the Janissaries, but there are lots of other instances of the military becoming a colossal useless but dangerous parasite,…
Sounds like current US. Military industrial complex just starts wars randomly, and does not bother with approval from senate.
In my country, any political problem real or perceived, and part of the population are already asking for the military to attempt a coup and fix things.