Third-party intervention in civil wars creates complex challenges. The Core Argument shows competitive interventions distort domestic bargaining processes by encouraging spoilers who prolong conflict for strategic advantage, leading to protracted intrastate conflicts. This introduces a counterintuitive finding that external involvement can sometimes beget more internal fighting than it aims to stop. The paper builds on this insight by outlining theoretically grounded propositions about intervention dynamics.

Evidence & Findings comes from analyzing all civil wars between 1975 and 2009 quantitatively, alongside a detailed qualitative case study of the Angolan conflict (1975-1991). This analysis reveals that competitive intervention patterns explain recent global decreases in both internal conflict prevalence and average duration.

Policy Implications highlight that understanding these unintended escalation effects is crucial for crafting effective strategies to prevent or resolve contemporary civil conflicts.