When and Whom to Join: The Expansion of Ongoing Violent Interstate Conflicts

Abstract

The opportunity and willingness framework has received much attention in research on interstate conflict expansion. This framework is extended here by examining when and what side third parties join during ongoing conflicts. It is maintained that without examining both timing and side selection, understanding of conflict expansion is limited. The timing and side joined in interstate disputes between 1816 and 2001 are analysed using a competing risks duration model. The findings contribute novel insights into many key debates in conflict research such as balancing versus bandwagoning, as well as alliance reliability and the democratic peace. The results also indicate that relying on statistical models that do not distinguish between which side a third party can join may produce misleading results.

Military Coalitions and Crisis Duration

“…The strategy we employ to identify our model stems from a large literature that emphasizes the importance of geography for conflict expansion. 21 More specifically, we exploit the finding that states in close proximity to a conflict, especially contiguous ones, are more likely to intervene (e.g., Siverson and Starr 1990, Siverson and Starr 1991, Joyce et al 2014. It is argued that this is because geographic proximity increases the feasibility of military involvement for a state.…”

Which wars spread? Commitment problems and military intervention

“…From a practical standpoint, the question matters as interstate wars which experience military intervention are longer and deadlier than those that do not (Shirkey 2012b;Slantchev 2004). While substantial progress has been made on which states are more likely to intervene (Altfeld and Bueno de Mesquita 1979;Richardson 1960;Siverson and Starr 1991;Valeriano and Vasquez 2010) 2 and when they are likely to do so (Joyce, Ghosn, and Bayer 2014;Melin and Koch 2010;Shirkey 2009;2012a), far less is known about which wars are likely to draw in outside states. I argue interstate wars caused by commitment problems are more likely to experience military intervention than are wars with other causes.…”

Going Above and Beyond: Dependence and Military Coalition Participation

“…The main causes contemplated in such works include a variety of factors, but unsurprisingly, previous alliance commitments are often considered to be a strong predictor of willingness, i.e., the probability of joining an ongoing war. Accordingly, I first focus mainly on Walt (1987) and Joyce, Ghosn, and Bayer (2014) to address these two programs. Because each are respectively considering alliances and war diffusion as opposed to IMC participation, their theories and findings are applied liberally throughout the discussion so as to apply to IMC participation.…”

“…27 Building on the earlier works of Siverson and Starr (1990), Joyce, Ghosn, and Bayer (2014) concisely summarize the "Opportunity and Willingness" argument as Opportunity is whether a state can join a conflict, and willingness is why they join. 28 Joyce, Ghosn, and Bayer expand upon Siverson and Starr's focus on borders(opportunity) and alliances(willingness) to include a state's material capability as an additional indicator of opportunity, and, alliances and regime type, as indicators of willingness.…”

“…30 Opportunity is the possibility of conflict. 31 As understood by Siverson and Starr (1990), and Joyce, Ghosn, and Bayer (2014), a state first has to be capable of war in order to join in on an ongoing conflict. Hence, the closer it is to a conflict, the more 'opportunity' it has to take part in it.…”