15 countries, conflict risk increases following a rise in commodity rents because leaders who do not allow collective action are more likely to have disorganized militaries. Insurgents confront lower costs of violently pursuing higher rents in these countries than in countries that exhibit significant constraints on the executive.

The validity of this alternative interpretation depends on what, exactly, the Polity measure of executive constraints captures. Keefer (2010b) shows that the subjective executive constraints measure is highly correlated with objective measures of political checks and balances, consistent with the interpretation traditionally given the variable in the literature. However, even after controlling for checks and balances, it is just as strongly associated with the age of the largest government party and the years of continuous competitive elections, both of which relate to the degree to which citizens can act collectively to hinder opportunistic behavior by leaders.

# **Other implications:  Predatory behavior, child soldiers, state capacity, ethnicity and service delivery**

Leaders‟ decisions to allow collective action affect numerous other issues in the study of conflict. Two are the problems of predation on civilian populations and the forced recruitment of child soldiers. Others relate to arguments that state capacity or ethnic fragmentation raise conflict risk. A fifth is the degree to which external agencies should focus on improved service delivery as a way to defuse the risk of conflict recurrence in postconflict countries. This section briefly reviews these.

# **Predation**

Predation by both soldiers and rebels on the local population is well-documented in many conflict settings, including the DRC.<sup>10</sup> Gates (2002) argues that predation is more likely when leaders cannot easily control shirking by their soldiers in their conflict effort, making them more tolerant of looting.<sup>11</sup> Humphreys and Weinstein (2006) argue that organization within fighting units (rather than the ability of leaders to supervise fighting units) drives predation. The evidence they assemble from Sierra Leone shows that fighting units that exhibited less discipline (e.g., more drunkenness or within-unit conflict) were more likely to predate on civilians. Kalyvas (2006) argues that violence against civilians could also be spurred by private efforts to settle scores. In all three approaches, predation is the consequence of the inability of leaders to prevent individual fighting units or soldiers from taking private actions that undermine, or at least do not contribute to, overall conflict success.

The earlier discussion about collective action bears directly on the contractual relationship between leaders and soldiers. If predation hurts conflict success, and if leaders can credibly promise future rewards based on conflict success, soldiers are less likely to predate. They are also more likely to support leader punishment of soldiers who predate, since such soldiers threaten the rewards of all soldiers. However, leaders (either of the entire group or of fighting units within the group) who fear a coup threat are likely to discourage 10 Predation here is understood as non-strategic violence undertaken by fighting units or individual soldiers in pursuit of their own private objectives.

11 Padró i Miquel and Yared (2009) examine a related issue in deriving the optimal strategy of a government interested in quelling local disturbances through the use of local actors who can do this at lower cost.