Drones will largely solve terrorism.
If you're a member of an old school hard religion that believes in chopping off the heads of anyone that says something you don't like you might want to rethink your life choices.
It is only a matter of a few years at most when the military will have the capability to release a swarm of smart drones with AI vision technology that can seek out and kill anyone they have a picture of. Smart phones have had the ability to do speech recognition for a while now. Vision or image processing in a small bird sized drone is the logical next step in AI technology and there is no technical reason preventing this from happening very soon.
So... if you are a member of an extreme terrorist organization it may be time to cut your losses and figure out how to live in the new world. Change is hard, but it is time to change or die. Sometimes great grandpa is wrong. Dinosaurs did exist and the world is more than 2000 years old.