Rivalry Drives States to Back Insurgents — And Raises Risk of Escalation

Why Do States Back Insurgents?

Zeev Maoz and Belgin San-Akca investigate when and why states choose to support non-state armed groups (NAGs) — such as insurgents, guerrillas, and terrorist organizations — that target their interstate rivals. The question matters because state support for NAGs can alter conflict dynamics, create proxies for coercion, and change the risks of wider escalation between states.

Theory: Calculated Cooperation

The authors develop a formal rational-choice model that treats state–NAG partnerships as purposive cooperation. Two central forces shape states' decisions: (1) dissatisfaction with the status quo (which raises the expected gains from using a proxy) and (2) the expected risk of retaliation by the rival (which raises the costs). The model predicts that ongoing interstate rivalries both encourage NAGs to form and make states more likely to provide resources, and that state backing of NAGs in turn increases the chance that a rivalry will escalate.

Data and Statistical Tests: Global Evidence, 1946–2001

Maoz and San-Akca test their propositions with an original dataset covering 175 non-state armed groups and 83 state supporters in the post–World War II period (1946–2001). Using statistical analysis of these cases, they assess whether rivalry presence and measures of dissatisfaction and retaliation risk predict state support, and whether support predicts subsequent escalation of rivalry.

Key Findings

• Rivalries make it more likely that states will cooperate with NAGs operating against their rivals.
• Indicators tied to dissatisfaction with the status quo and manageable retaliation risks increase the probability of state support.
• State sponsorship of NAGs is associated with a higher likelihood of rivalry escalation.

What This Means for Theory and Policy

The results support a strategic, cost–benefit understanding of proxy relationships: states do not merely opportunistically exploit non-state groups, they make calculated choices shaped by rivalry dynamics and perceived risks. For policymakers, the findings underscore that backing insurgent partners can deepen interstate tensions and produce spillover escalation, suggesting caution in using NAGs as instruments of foreign policy.