The phrase "greed versus grievance" or "greed and grievance" refers to the two baseline arguments put forward by scholars of armed conflict on the causes of civil war, though the argument has been extended to other forms of war, such as violent conflict in general, rebellion and insurgency, for example.
"Greed" is shorthand for the argument that combatants in armed conflicts are motivated by a desire to better their situation, and perform an informal cost-benefit analysis in examining if the rewards of joining a rebellion are greater than not joining. "Grievance" stands for the argument that people rebel over issues of identity, e.g. ethnicity, religion, social class, etc., rather than over economics. In practice, even proponents of strong versions of these arguments admit that the opposing argument has some influence in the development of a conflict.
Whether the cause of war is attributed to 'greed' or 'grievance' the common factor is the perception of a certain deprivation. If it is an economic deprivation, the inequality will be a 'vertical inequality' and the cause of war will be 'greed'. If the deprivation is caused by ethnicity, age, religion or gender, it will be a 'horizontal inequality' and the cause of war will be due to the 'grievances'.
Cornerstones
The "greed versus grievance" theory provides opposing arguments on the cause of civil war. Proponents of the greed argument posit that armed conflicts are caused by a combatant's desire for self-enrichment. These motivations are manifested in multiple ways, including economic gain through control of goods and resources or by increased power within a given state. Conflicts started through greed are often seen in states with negative economic growth and/or systemic poverty, as this implies limited state capacity to provide opposition groups with economic concessions as well as the likelihood of the absence of an effective military or police apparatus to contend with those seeking power or resources.
Collier-Hoeffler Model
The strong case for the "greed" argument was made by Paul Collier and Anke Hoeffler in a study they performed for the World Bank in 2000. Since then, the Collier-Hoeffler Model has been the focus of much of the greed-grievance debate.
Paul Collier and Anke Hoeffler wrote one of the seminal pieces defending greed over grievance. They found that factors that increase the military or financial viability of rebellion correlated with more instances of conflict than factors leading to grievances. They argue that certain natural resources such as oil are tied to increased likelihood of conflict onset, and other natural resources such as diamonds are tied to increases in conflict duration. This is because natural resources may lower the startup cost of war, and provide rebels with an easy way of financing prolonged conflicts. Natural resources may also make the state a more lucrative prize for capture, further decreasing the opportunity cost of insurgency. For the same reason, Collier and Hoeffler also conclude that states with low per capita GDP are more likely to experience civil war, because low average income makes wage earning through conflict a more lucrative prospect. Collier and Hoeffler also make an important distinction between preferences and constraints in terms of circumstances that favor rebellions. Societies can be more prone to conflict because preferences for rebellion are unusually strong or because constraints on rebellion are unusually weak – the former being aligned with grievance and the latter with greed. Measures such as democracy or political repression are hard to draw conclusions from because they may increase grievances among some groups, but empower other groups to repress potential insurgents. While most states harbor some level of grievance with the sitting regime, few states experience civil war. This is because although not everyone is content with the established order, rebellion only occurs when conflict is a viable option for dissatisfied parties. Therefore, Collier and Hoeffler conclude that on their own, most variables that seek to explain civil war onset through measurements of grievance alone prove insufficient. Instead Collier and Hoeffler advocate using the looking at greed, that is to say the opportunity cost of initiating and sustaining conflict. Fearon and Laitin (2003) offer a contrasting view. They see opportunity structures created by weakness state capacity to be a cause of civil war onset. They find evidence in favor of the technology of insurgency as a mechanism. Further, they find that ethnicity, religion or any cultural or demography characteristic do not seems to have a positive relationship with civil war onset.