The closest answer to terrorism is, let everybody carry and wear guns. This way, if terrorists attack, there is a chance that some of the people can save themselves. When the terrorists find out that the people are ready to defend themselves, they will be less likely to attack; they fear death most of the time just like everybody else.
Sure, there will be mistakes made. There will be some injury and death from friendly fire. But when the terrorists realize that the people mean business, they will go away, and the crooks and criminals right along with them.
Wearing guns, and using them at the right time, means peace.