A prominent qualification of the democratic peace holds that states undergoing incomplete democratization while their political institutions are weak are unusually prone to external war. Narang and Nelson (2009) showed that the empirical record for this claim rests on a dearth of cases, a single historical episode (the dismemberment of the Ottoman Empire before World War I), and contestable coding decisions, and they specified what would be needed to settle the question: validated measures of the causal mechanism, replicable historical coding protocols, and tests against external-conflict outcomes short of interstate war. This problem asks whether incomplete democratization with weak institutions makes states more externally belligerent than other regime trajectories, and through what mechanism, taking account of war, militarized disputes below the war threshold, coercive diplomacy, and spillovers from internal conflict. The literature through 2026 leaves the question contested rather than resolved.

Background

The democratic peace — the observation that pairs of stable democracies almost never fight interstate wars against one another — is among the most robust regularities in international relations. Its most influential qualification was advanced by Mansfield and Snyder (1995; 2005): the process of democratization can be dangerous. In a state undergoing an incomplete democratic transition (a regime that becomes more democratic but stalls without completing the transition, typically in a hybrid form between autocracy and democracy) while central political institutions are weak, mass political participation outruns institutional restraint. This gives both rising and declining elites the motive and the opportunity to play the nationalist card to rally popular support against domestic and foreign rivals, raising the risk of external war. The claim is often called the transition exception to the democratic peace.

The empirical debate relies on standard datasets and conventions. Regime type is usually measured with the Polity data, a composite index scoring states from autocracy to democracy on a −10 to +10 scale, built from subindicators, one of which indexes the domestic concentration of political power and was not updated in later Polity releases; critics argue these indicators may not cleanly identify the specific incomplete-transition-plus-weak-institutions combination the theory requires. Interstate wars are identified with the Correlates of War (COW) project's list of wars, and a key convention distinguishes states that merely participate in an ongoing war from those that initiate it — a distinction that matters because responsibility for initiation is genuinely contestable in many historical episodes. Below the war threshold, militarized interstate disputes (MIDs) — confrontations involving explicit threats, displays, or uses of force that do not reach the COW war threshold — provide a finer-grained measure of belligerence.

Narang and Nelson (2009) reassessed the Mansfield–Snyder claim and found the empirical support wanting: very few observations exist in which incomplete democratizers with weak institutions actually participated in war; the statistical association between incomplete democratization and war depends entirely on the Ottoman Empire's dismemberment before World War I; and the historical cases Mansfield and Snyder emphasize rarely involve the theorized regime type. They concluded that the finding is not supported by the data, and they identified why the question cannot yet be settled: existing operational measures may not capture the theory's causal components; assigning responsibility for war initiation is intrinsically difficult for some episodes; inference is sensitive to defensible but different historical codings, such as whether the Ottoman Empire's 1911–1913 Balkan campaigns are treated as separate wars or as one multipart campaign; and external aggression short of interstate war — militarized interstate disputes, coercive diplomacy, and spillovers from internal conflict — has not been examined. Mansfield and Snyder (2009) replied in the same journal issue, restating their theory that incomplete transitions in countries lacking the institutional capacity to sustain democratic politics raise the risk of both international and civil war. The dispute has not been adjudicated since.

Problem Statement

Determine whether states undergoing incomplete democratization combined with weak political institutions are more externally belligerent than other states — the transition exception to the democratic peace — and through what mechanism. External belligerence spans interstate war onset and participation, militarized interstate disputes short of war, coercive diplomacy, and spillovers from internal conflict.

References

  1. Narang, Vipin, and Rebecca M. Nelson. 2009. "Who Are These Belligerent Democratizers? Reassessing the Impact of Democratization on War." International Organization 63(2): 357–379. DOI: 10.1017/S0020818309090122. https://doi.org/10.1017/S0020818309090122
  2. Mansfield, Edward D., and Jack L. Snyder. 1995. "Democratization and the Danger of War." International Security 20(1): 5–38. DOI: 10.2307/2539213. https://doi.org/10.2307/2539213
  3. Mansfield, Edward D., and Jack L. Snyder. 2005. Electing to Fight: Why Emerging Democracies Go to War. Cambridge, MA: MIT Press. DOI: 10.7551/mitpress/2660.001.0001. https://doi.org/10.7551/mitpress/2660.001.0001
  4. Mansfield, Edward D., and Jack L. Snyder. 2009. "Pathways to War in Democratic Transitions." International Organization 63(2): 381–390. DOI: 10.1017/S0020818309090134. https://doi.org/10.1017/S0020818309090134
  5. Bogaards, Matthijs. 2010. "Measures of Democratization: From Degree to Type to War." Political Research Quarterly 63(2): 475–488. DOI: 10.1177/1065912909358578. https://doi.org/10.1177/1065912909358578
  6. Cederman, Lars-Erik, Simon Hug, and Lutz F. Krebs. 2010. "Democratization and Civil War: Empirical Evidence." Journal of Peace Research 47(4): 377–394. DOI: 10.1177/0022343310368336. https://doi.org/10.1177/0022343310368336
  7. Bernhard, Michael, Ömer Faruk Örsün, and Reşat Bayer. 2017. "Democratization in Conflict Research: How Conceptualization Affects Operationalization and Testing Outcomes." International Interactions 43(6): 941–966. DOI: 10.1080/03050629.2017.1257489. https://doi.org/10.1080/03050629.2017.1257489
  8. Hegre, Håvard. 2014. "Democracy and Armed Conflict." Journal of Peace Research 51(2): 159–172. DOI: 10.1177/0022343313512852. https://doi.org/10.1177/0022343313512852
  9. Bogaards, Matthijs. 2023. "Refreshing Our Memory of a Classic: Mansfield and Snyder's Electing to Fight." Civil Wars 25(2–3): 589–594. DOI: 10.1080/13698249.2023.2253046. https://doi.org/10.1080/13698249.2023.2253046
  10. Babayev, Azar, and Kamran Mahmudov. 2023. "The Provocative Effects of Democratization: Assessing the Relationship Between the Regime Transition in Armenia and the Escalation of the Karabakh Conflict in 2018–2020." Democratization 30(5): 894–913. DOI: 10.1080/13510347.2023.2195168. https://doi.org/10.1080/13510347.2023.2195168
  11. Howe, Brendan M. 2026. "Democratization and International Conflict During and After the Third Wave." Democratization 33(3): 516–537. DOI: 10.1080/13510347.2025.2537854. https://doi.org/10.1080/13510347.2025.2537854
  12. Boldt, Damian. 2026. "Democratic Transitions and International Conflict." International Interactions 52(1): 124–153. DOI: 10.1080/03050629.2025.2609092. https://doi.org/10.1080/03050629.2025.2609092