This is currently a hot political topic, but what does the science say?
I was thinking that a good experiment would take groups of people, and match them for alternate explanations: Age, gender, socio-economic status, level of education, nationality, occupation, cultural factors, political affiliation, immigration status, etc. (These are factors that many experiments control for when dividing subjects into groups, so is not unusual to do.) Then look for correlations, and see if particular religious affiliations (or non-believers), are more strongly correlated with participation in acts of political violence than are other factors.
I have not found such a study yet. There is a fair amount of research regarding attitudes towards violence, with mixed results (example, example, example, exampleexample), but these are generally not controlled for very many factors, and do not address any actual violence rates. There is also some research on actual violence rates (example, example), but again, few variables are controlled for, and the focus is on countries rather than people.
Is religious affiliation really a predisposing factor for people to actually commit acts of terrorism and politically-motivated violence?