What causes Failed States?

A complete lack of trust. A total breakdown of the institutions of Government. A return to tribal or gang related behavior. Or (what is happening all across the middle East and parts of Africa) right now.

Another cause is overpopulation where the poor have no future at all. So, if they want to live they have to join some kind of gang, do illegal things and likely to kill others to live.

All these things happened to Somalia "see Blackhawk Down" which is where this problem first started.

But, you basically will see the same things that cause failed states arise from Groups like ISIL(ISIS) and Boko Haram. Whenever gangs of young poor men with Kalashnikovs sprout up and no one stops them, Chaos has won. Overpopulation has won.

And most importantly civilization has lost until some sort of balance has returned. (usually when most people in that area have died from these gangs.)

However, to a greater or lesser degree Somalia has somewhat now remained a failed state since the early 1990s when Clinton was president. So, this sort of thing could also be the result in Syria,Northern Iraq, Yemen and other places as well over the years to come.

And the real problem with this for the world is these sorts of places are a natural seedbed for anarchy and terrorism of all kinds, and filled with people with major PTSD who are more like animals than civilized people. This ends civilizations in these areas sometimes for years or decades because everything returns to the law of the jungle where no one is safe anymore.