Root causes is the idea that crime and terrorism are caused by poverty and idleness.
The literature has been stunningly silent on how Katrina showed how wrong this view is: crime went down after Katrina, way down, because all the targets had moved away. Root causes would suggest that it would have picked up due to the destruction of wealth and livelihoods. Didn’t happen. Here’s some supporting evidence from Baltimore.
Now we have this piece from the Journal of Conflict Resolution. It shows that when unemployment goes up, terrorism goes down.
One is that insurgents are prompted to act when the economy is doing well, because the resources and land that insurgents want to seize are more valuable. Another theory posits that when unemployment is high, governments find more willing sellers of intelligence about insurgency efforts. Still another theory asserts a different kind of causality: The checkpoints and other security measures that suppress insurgent violence also hamper local economies, driving up unemployment.
Via Marginal Revolution.