What causes terrorism?

In light of the terrorist plot dominating today's news, some readers might be interested in this article from the Journal of Economic Perspectives: Education, Poverty and Terrorism: Is There a Causal Connection? by Alan B. Krueger and Jitka Maleckova. Their bottom line:

The evidence we have presented, tentative though it is, suggests little direct connection between poverty or education and participation in terrorism.

Sadly, we still know relatively little about the root causes of terrorism.

Update: Other research suggests that educated terrorists are more likely to be successful. So education seems to have negative externalities for this population: It does not reduce participation in terrorist activity, but it increases the efficacy of the terrorists.