Some governments, however, give such considerations short shrift.These governments are not interested in state-building and in extreme cases they have carried out counter-insurgency operations by using mass murder, genocide, terror, torture and execution.Guerrilla warfare is a form of irregular warfare in which a small group of combatants, such as paramilitary personnel, armed civilians, or irregulars, use military tactics including ambushes, sabotage, raids, petty warfare, hit-and-run tactics, and mobility to fight a larger and less-mobile traditional military. This term became popular during the early-19th century Peninsular War, when the Spanish people rose against the Napoleonic troops and fought against a highly superior army using the guerrilla strategy.The term "guerrilla" was used in English as early as 1809 to refer to the fighters (e.g., "The town was taken by the guerrillas"), and also (as in Spanish) to denote a group or band of such fighters.Communist leaders like Mao Zedong and North Vietnamese Ho Chi Minh both implemented guerrilla warfare giving it a theoretical frame which served as a model for similar strategies elsewhere, such as the Cuban "foco" theory and the anti-Soviet Mujahadeen in Afghanistan.Mao Zedong summarized basic guerrilla tactics at the beginning of the Chinese "Second Revolutionary Civil War" as: "The enemy advances, we retreat; the enemy camps, we harass; the enemy tires, we attack; the enemy retreats, we pursue." While the tactics of modern guerrilla warfare originate in the 20th century, irregular warfare, using elements later characteristic of modern guerrilla warfare, has existed throughout the battles of many ancient civilizations but in a smaller scale.
Evidence of conventional warfare, on the other hand, did not emerge until 3100 BC in Egypt and Mesopotamia.
Since the Enlightenment, ideologies such as nationalism, liberalism, socialism, and religious fundamentalism have played an important role in shaping insurgencies and guerrilla warfare.