Terrorist organizations can be domestic. Terrorism is simply defined as using fear/threat (usually of violence) to influence someone's behaviour. If school sh

Terrorist organizations can be domestic. Terrorism is simply defined as using fear/threat (usually of violence) to influence someone's behaviour. If school shooters were perhaps anti-gun proponents, one could say they were terrorists trying to get people to introduce stricter gun control rules. But most of them don't have any causes of the sort.