Terrorism
Terrorist acts frequently have a political purpose. Some official, governmental definitions of terrorism use the criterion of the illegitimacy or unlawfulness of the act. to distinguish between actions authorized by a government (and thus "lawful") and those of other actors, including individuals and small groups. For example, carrying out a strategic bombing on an enemy city, which is designed to affect civilian support for a cause, would not be considered terrorism if it were authorized by a government. This criterion is inherently problematic and is not universally accepted, because: it denies the existence of state terrorism. An associated term is violent non-state actor.
Definitions of terrorism
The U.S. Department of Defense recently changed its definition of terrorism. Per Joint Pub 3-07.2, "Antiterrorism," (24 November 2010), the Department of Defense defines it as "the unlawful use of violence or threat of violence to instill fear and coerce governments or societies. Terrorism is often motivated by religious, political, or other ideological beliefs and committed in the pursuit of goals that are usually political."