In its search for factors contributing to the brutal, indiscriminate violence that characterizes some civil wars, this book has concentrated on the significance of rebel organizations. It is because of variation in the characteristics of insurgent movements that, despite the presence of conditions that facilitate armed opposition to the state, some civil wars produce insurgents that seek to transform governance while others give rise to predatory organizations that sow terror among noncombatant populations. I have argued that variation in the barriers that exist to the organization of insurgency – in particular, whether insurgent groups have access to material resources – helps us to account for the different characteristics of rebel groups.

The theory is simple and concise. It is also consistent with the logic of state building in the modern world. Leaders that face strong incentives to secure the consent of the governed, and the tax revenues that accompany consent, have tended to build states that protect the security and rights of their constituents. But it may be too simple. In emphasizing structure over agency, it underlines the importance of constraints and ignores the ability of political actors to shape the environments in which they operate. Perhaps differences in leadership are what explain the divergent behavior of insurgent groups.

This requires a return to an issue first raised in the introduction: the fact that a group's initial endowments may be shaped by the actions of its leaders.