Why do coups d’état happen? Although many studies have investigated this question, they pay relatively little attention to the international causes and ramifications of coups. Especially, empirical studies on the external determinants of coup risk and outcomes still remain limited. There are two current lines of research in this direction. The first line studies international linkages and coup risk, looking at the external determinants of coups: regional spillover effects, foreign linkage, and foreign leverage. A promising angle on this front is focusing on the role of post-coup reactions from international actors to illuminate how coup plotters shape their incentives under outside pressure. The second line of research investigates interstate conflict and coup risk, considering diversionary behavior and external threats as potential coup-proofing strategies. In this effort, studying the relationship between external threat environment and coup risk can be fruitful, whereas empirical tests of the classical diversionary war theory will yield relatively marginal contributions.
Currently, three issues stand out in the empirical coup literature that should be further addressed by scholars. First is the need for more extensive and systematic data collection efforts to obtain detailed information about the identities, targets, and motives of coup perpetrators. Second, the external sources of leader insecurity beyond interstate conflicts remain an underexplored area. Third, although many studies have tried to determine when coup attempts happen, scholarly knowledge of when and how they succeed remains very limited. More work is needed to uncover the determinants of coup success across different regimes and leader survival scenarios.