Terrorism is not Effective: http://www.gwern.net/Terrorism%20is%20not%20Effective

Terrorism is not About Terror: http://www.gwern.net/Terrorism%20is%20not%20about%20Terror

Just look at the statistics. The total number of people killed by terrorists is negligible. And 0 terrorist groups have ever won and achieved their stated goals.

I remember the Boston bombing. That same week, there was another explosion at a chemical plant that killed many more people, and blew up a nursing home. Guess which event got more press, by a large amount? Which event are people more likely to remember? Can you even name what city the chemical plant exploded in or remember any details about it?

Why is this? It's because people react to violence much differently than they react to accidents. Because thousands of years ago, violence was the one cause of death you could do something about. If you got an infection, or if a natural disaster struck, or a famine broke out, etc, those are all out of your control. But if someone was a threat to your family or tribe, you could fight them, or flee from them.

We have many emotions and social instincts whose entire purpose is to deal with other humans that threaten us. Like paranoia, anger, and hate. No one hates the chemical plant, and wants to go kill it. People hate the Tsarnaev brothers.

Blow up enough people often enough and fear and panic will become pervasive. People stop opening their shops, investments stop coming.

Terror is a pretty effective way to overthrow a gov't.