Political violence is violence perpetrated by people or governments to achieve political goals. It can describe violence used by a state against other states (war) or against non-state actors (most notably police brutality, counter-insurgency or genocide). It can also describe politically-motivated violence by non-state actors against a state (rebellion, rioting) or against other non-state actors. Non-action on the part of a government can also be characterized as a form of political violence, such as refusing to alleviate famine or otherwise denying resources to politically identifiable groups within their territory. Political violence is violence perpetrated by people or governments to achieve political goals. It can describe violence used by a state against other states (war) or against non-state actors (most notably police brutality, counter-insurgency or genocide). It can also describe politically-motivated violence by non-state actors against a state (rebellion, rioting) or against other non-state actors. Non-action on the part of a government can also be characterized as a form of political violence, such as refusing to alleviate famine or otherwise denying resources to politically identifiable groups within their territory. Due to the imbalances of power between state and non-state actors, political violence often takes the form of asynchronous warfare where neither side is able to directly assault the other, instead relying on tactics such as terrorism and guerrilla warfare, and often include attacks on civilian or otherwise non-combatant targets that are perceived as a proxy for the opposing faction. Many groups and individuals believe that their political systems will never respond to their demands and thus believe that violence is not only justified but also necessary in order to achieve their political objectives. Similarly, 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. Political violence varies widely in form, severity, and practice. In political science, a common organizing framework is to consider types of violence by the relevant actors: violence between non-state actors, one-sided violence perpetrated by a state actor against civilians, and violence between states. Fighting between non-state actors without state security forces playing a direct role in the conflict. An ethnic conflict is fought between ethnic groups. While at times a specific ethnic group may have the backing (whether formal or informal) of the state (or conversely, a specific ethnic group may be targeted by the state), ethnic conflict can also take place between two groups without the direct intervention of the state, or despite the state's attempts to mediate between groups. Terrorism can be directed by non-state actors against political targets other than the state (e.g. Stabbing attacks at gay pride parades in Jerusalem, Charlie Hebdo shooting). Because terrorism is a tactic often used by the weaker side of a conflict, it may also fall under violence between a state and non-state actor. While there lacks a concrete definition of terrorism, the United States Department of Defense however defines terrorism as, 'the calculated use of unlawful violence or threat of unlawful violence to inculcate fear; intended to coerce or to intimidate governments or societies in the pursuit of goals that are generally political, religious, or ideological.' What is and is not considered terrorism is itself a controversial political question, as states have often used the label of terrorism to exclusively demonize the actions of their enemies while obscuring 'legal' violence administered by the state (e.g. The Troubles, CPP–NPA–NDF rebellion, 2014 Israel–Gaza conflict). The use of force by an organized armed group, be it a government or non-state group, which results in the deaths of civilians. According to the Human Security Report Project, a campaign of one-sided violence is recorded whenever violence against civilians committed by one group results in at least 25 reported deaths in a calendar year. One form of political violence is genocide. Genocide is commonly defined as 'the deliberate and systematic destruction, in whole or in part, of an ethnic, racial, religious, or national group', although what constitutes enough of a 'part' to qualify as genocide has been subject to much debate by legal scholars. Genocide is typically carried out with either the overt or covert support of the governments of those countries where genocidal activities take place. The Holocaust is the most cited historical example of genocide.