Speaking with one voice: Coalitions and wartime diplomacy

ABSTRACT

When and why do countries in a wartime coalition engage in diplomacy during hostilities? This paper establishes a theoretical framework of coalitional diplomacy that highlights each member’s private costs and benefits to fighting or seeking a negotiated exit. I argue that the propensity for coalition members to engage in negotiations is a function of the coalition’s balance of military contributions, as well as the coalition’s battlefield successes and failures. Evidence supporting these claims stem from a large-scale quantitative analysis of two centuries of interstate wars, as well as a close study of the Allies in the Crimean War.

KEYWORDS:

• Coalition
• war
• interstate war
• negotiation
• diplomacy

Acknowledgements

I thank Rosella Capella Zielinski, Ryan Grauer, Barbara Elias, Stepfanie von Hlatky, Thomas Juneau, and Dan Reiter for helpful comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here.

Notes

¹ Ajin Choi, ‘Fighting to the Finish: Democracy and Commitment in Coalition War’, Security Studies 21/4 (2012), 624–653; Alex Weisiger, ‘Exiting the Coalition: When Do States Abandon Coalition Partners during War?’, International Studies Quarterly 60/4 (2016), 753–765.

² Daniel S. Morey, ‘Military Coalitions and the Outcome of Interstate Wars’, Foreign Policy Analysis 12/4 (2016), 533–551.

³ Atsushi Tago, ‘Determinants of Multilateralism in US Use of Force: State of Economy, Election Cycle, and Divided Government’, Journal of Peace Research 42/5 (2005), 146–157.

⁴ James D. Fearon, ‘Rationalist Explanations for War’, International Organization 49/3 (1995), 379–414.

⁵ Robert Powell, ‘War as a Commitment Problem’, International Organization 60/1 (2006), 169–203.

⁶ Bahar Leventoğlu and Branislav L. Slantchev, ‘The Armed Peace: A Punctuated Equilibrium Theory of War’, American Journal of Political Science 51/4 (2007), 755–771.

⁷ Eric Min, ‘Talking While Fighting: Understanding the Role of Wartime Negotiations’, International Organization 74/3 (2020), 610–632.

⁸ Michael G. Findley, ‘Bargaining and the Interdependent Stages of Civil War Resolution’, Journal of Conflict Resolution 57/5 (2012), 905–932; Jeffrey M. Kaplow, ‘The Negotiation Calculus: Why Parties to Civil Conflict Refuse to Talk’, International Studies Quarterly 60/1 (2016), 38–46.

⁹ Oriana S. Mastro, The Costs of Conversation: Obstacles to Peace Talks in Wartime (Ithaca, NY: Cornell University Press 2019).

¹⁰ Morey, ‘Military Coalitions’; Patricia A. Weitsman, Waging War: Alliances, Coalitions, and Institutions of Interstate Violence (Stanford, CA: Stanford University Press 2014).

¹¹ See also Rosella Capella Zielinski and Ryan Grauer, ‘Organizing for performance: coalition effectiveness on the battlefield’, European Journal of International Relations 26/4 (2020), 953–978. In the quantitative analysis, I define a measure of coalition asymmetry that can range between 1/n (identical contributions by all n members) and 1 (all contributions from a single member). The median level of asymmetry across all wartime coalitions is 0.66. This number is calculated after omitting all belligerents that fight alone. Coalitions with asymmetry measures lower than 0.66 can be considered more symmetric, while those higher than 0.66 are more asymmetric.

¹² Returning briefly to the hunting metaphor, group members that manage to tightly surround a stag will be more likely to continue their pursuit, while members of a group repeatedly injured by an aggressive stag may consider seeking rabbits instead.

¹³ Kristopher W. Ramsay, ‘Information, Uncertainty, and War’, Annual Review of Political Science 20/1 (2017), 505–527; Dan Reiter, ‘Exploring the Bargaining Model of War’, Perspectives on Politics 1/1 (2003), 27–43.

¹⁴ Scott Wolford, ‘The Problem of Shared Victory: War-Winning Coalitions and Postwar Peace’, Journal of Politics 79/2 (2017), 702–716.

¹⁵ Micheal Clodfelter, Warfare and Armed Conflicts: A Statistical Encyclopedia of Casualty and Other Figures, 1494–2007 (Jefferson, NC: McFarland & Company 2017), 317–318. Based on these totals, the coalition’s asymmetry measure is 0.74, which is higher than the observed median of 0.66 (see footnote 11).

¹⁶ Chris Leuchars, To the Bitter End: Paraguay and the War of the Triple Alliance (Westport, CT: Greenwood Press 2002).

¹⁷ Weisiger, ‘Exiting the Coalition’.

¹⁸ Branislav L. Slantchev, ‘The Principle of Convergence in Wartime Negotiations’, American Political Science Review 97/4 (2003), 621–632; Suzanne Werner and Amy Yuen, ‘Making and Keeping Peace’, International Organization 59/2 (2005), 261–292.

¹⁹ Clodfelter, Warfare and Armed Conflicts, 324. This coalition’s asymmetry value using these strengths is 0.72, which is higher than the median of 0.66 (see footnote 11).

²⁰ Jorge G. Granier, United States and the Bolivian Seacoast (La Paz, Bolivia: Ministerio de Relaciones Exteriores y Culto 1988).

²¹ William J. Dennis, Documentary History of the Tacna-Arica Dispute (Iowa City, IA: University of Iowa 1927).

²² Using the UNC’s personnel figures from late 1950, the UNC’s asymmetry measure is approximately 0.25, which is lower than the median of 0.66 for all coalitions in my data (see footnote 11).

²³ George F. Kennan, Memoirs, 1950–1963 (Boston, MA: Little, Brown 1972).

²⁴ At the risk of stretching the stag hunt analogy too far, hunters that have surrounded a stag may race one another to kill the stag and take as much of the best meat for themselves as possible before the other hunters do.

²⁵ Scott Wolford, ‘The Problem of Shared Victory: War-Winning Coalitions and Postwar Peace’, Journal of Peace 79/2 (2017), 702–716.

²⁶ This coalition’s asymmetry measure using these numbers is 0.57, which is lower than the median value of 0.66 across all coalitions in my dataset (see footnote 11).

²⁷ Geoffrey Wawro, The Austro-Prussian War: Austria’s War with Prussia and Italy in 1866 (Cambridge: Cambridge University Press 1993).

²⁸ Bolton King, A History of Italian Unity: Being a Political history of Italy from 1814 to 1871, Volume II (London: Nisbet & Co. 1899).

²⁹ Alexander Lanoszka and Michael A. Hunzeker, ‘Rage of Honor: Entente Indignation and the Lost Chance for Peace in the First World War’, Security Studies 24/4 (2015), 662–695.

³⁰ Section A of the Appendix features a complete list of coalition wars.

³¹ Morey, ‘Military Coalitions’.

³² Min, ‘Talking While Fighting’; Eric Min, ‘Interstate War Battle dataset (1823–2003)’, Journal of Peace Research 58/2 (2021): 294–303.

³³ Trevor N. Dupuy, Understanding War: History and Theory of Combat (New York: Paragon House 1987).

³⁴ Min, ‘Interstate War Battle dataset (1823–2003)’.

³⁵ David Eggenberger, An Encyclopedia of Battles: Accounts of Over 1,560 Battles from 1479 B.C. to the Present’ (New York: Dover Publications 1985); Tony Jaques, Dictionary of Battles and Sieges: A Guide to 8,500 Battles from Antiquity through the Twenty-first Century (Westport, CT: Greenwood Press 2007).

³⁶ Robert L. Helmbold, ‘Personnel Attrition Rates in Historical Land Combat Operations: A Catalog of Attrition and Casualty Data Bases on Diskettes Usable with Personal Computers’, Defense Technical Information Center, ADA279069 (1993).

³⁷ William Easterly and Ross Levine, ‘Africa’s Growth Tragedy: Policies and Ethnic Divisions’, Quarterly Journal of Economics 112/4 (1997), 1203–1250.

³⁸ J. David Singer, ‘Reconstructing the Correlates of War Dataset on Material Capabilities of States, 1816–1995’, International Interactions 14/2 (1987), 115–132.

³⁹ Full results in Section C of the Appendix show that results are unaffected by removing side-war-days where the side is a single state. They are also not affected by using a 30-day or 90-day temporal window for battlefield momentum, nor are they changed by removing the Korean War (where the United States wielded full operational control of the United Nations Command).

⁴⁰ Refer to Section D in the Appendix. See also Weisiger, ‘Exiting the Coalition’.

⁴¹ Bernadotte E. Schmitt, ‘The Diplomatic Preliminaries of the Crimean War’, American Historical Review 25/1 (1919), 36–67.

⁴² Winfried Baumgart, The Crimean War, 1853–1856 (London, Arnold 1999), 14.

⁴³ Clodfelter, Warfare and Armed Conflicts, 180.

⁴⁴ Both figures are also lower than the median asymmetry value of 0.66 observed across all coalitions (see footnote 11).

⁴⁵ David Wetzel, The Crimean War: A Diplomatic History (New York: Columbia University Press 1985).

⁴⁶ Henry M. Stephens, Syllabus of Eighty-seven Lectures on Modern European History (New York: Macmillan 1899).

⁴⁷ Gavin B. Henderson, ‘The Two Interpretations of the Four Points, December 1854’, English Historical Review 52/205 (1937), 48–66.

⁴⁸ Clive Ponting, The Crimean War: The Truth Behind the Myth (London: Chatto & Windus 2004), 216–217.

⁴⁹ Andrew Lambert, The Crimean War: British Grand Strategy against Russia, 1853–56 (Burlington, VT: Greenwood Press 2002).

⁵⁰ Paul W. Schroeder, Austria, Great Britain, and the Crimean War (Ithaca, NY: Cornell University Press 1972).

⁵¹ Baumgart, The Crimean War.

⁵² Ponting, The Crimean War, 315–316.

⁵³ J. B. Conacher, Britain and the Crimea 1855–56: Problems of War and Peace (New York: Palgrave Macmillan 1988), 154.

⁵⁴ Erik Goldstein, Wars and Peace Treaties: 1816–1991 (New York: Routledge 1992), 28.

⁵⁵ Stuart E. Johnson, ‘In This Issue’, Joint Force Quarterly 3/1 (1993–4), 6.

⁵⁶ Winston S. Churchill, Marlborough: His Life and Times (New York: Charles Scribner’s Sons 1937), 246.

⁵⁷ Joint Chiefs of Staff, Multinational Operations, Joint Publication 3–16 (2019); Kathleen J. McInnis, ‘Lessons In Coalition Warfare: Past, Present and Implications for the Future’, International Politics Reviews 1/1 (2013), 78–90.

Additional information

Funding

The data used in this work was partially supported by the National Science Foundation’s Graduate Research Fellowship #DGE-114747.

Notes on contributors

Eric Min

Eric Min is Assistant Professor of Political Science at UCLA. He received his Ph.D. in Political Science from Stanford University, where he was the Zukerman Postdoctoral Fellow at the Center for International Security and Cooperation for the 2017-2018 academic year. He is a 2020 Henry Frank Guggenheim Foundation Distinguished Scholar. His research interests focus on the application of machine learning, text, and statistical methods to the analysis of interstate war, diplomacy, and conflict management. His research has been published in American Political Science Review, International Organization, and Journal of Peace Research.