Political violence is a common means used by people and governments around the world to achieve political goals. Many groups and individuals believe that their political systems will never respond to their political demands. As a result they believe that violence is not only justified but also necessary in order to achieve their political objectives. By the same token, many governments around the world believe they need to use violence in order to intimidate their populace into acquiescence. At other times, governments use force in order to defend their country from outside invasion or other threats of force and to coerce other governments or conquer territory.