a1 Center for Comparative and International Studies at ETH Zürich and University of Zürich, Switzerland. E-mail: firstname.lastname@example.org
a2 University of Essex, United Kingdom, and Peace Research Institute, Oslo, Norway. E-mail: email@example.com
a3 University of North Texas, Denton, and the Social Conflict in Africa Database project. E-mail: firstname.lastname@example.org
a4 ETH Zürich, Switzerland. E-mail: email@example.com
A series of studies has shown that civil wars are caused not only by factors inside countries, but also by effects operating across state borders. Whereas a first wave of quantitative studies demonstrated that such effects make the “closed-polity” assumption untenable, more recently researchers have identified particular causal mechanisms driving conflict. Despite these recent advances, a central puzzle remains unresolved, namely why ethnic groups that at least in theory could count on support from large transborder ethnic kin (TEK) groups often have remained surprisingly peaceful, such as the stranded Russian populations in the “near abroad.” We propose a theoretical framework that extends the analysis from the primary dyad between the incumbent and the challenger group by adding a secondary dyad that pits the incumbent against the TEK group. We postulate a curvilinear effect of the TEK group's relative size on conflict onset. Using a new data set on transnational ethnic links, we find that that the risk of conflict increases within the middle range of the size spectrum, consistent with our main hypothesis. This means that large TEK groups have a conflict-dampening effect, provided that they control their own state. Excluded TEK groups, however, are not associated with lower conflict probabilities.
Lars-Erik Cederman is Professor of International Conflict Research at ETH Zürich and Director of the Center for Comparative and International Studies at ETH Zürich and University of Zürich, Switzerland. E-mail: firstname.lastname@example.org
Kristian Skrede Gleditsch is Professor of Government at the University of Essex, United Kingdom, and a research associate at the Peace Research Institute Oslo, Norway. E-mail: email@example.com
Idean Salehyan is Associate Professor of Political Science at the University of North Texas, Denton, and the co-director of the Social Conflict in Africa Database project. E-mail: firstname.lastname@example.org
Julian Wucherpfennig is Postdoctoral Fellow at ETH Zürich, Switzerland. E-mail: email@example.com
An earlier version of this research note was presented at the annual meeting of the American Political Science Association, Seattle, 2 September 2011. We are grateful for the helpful comments by Stephen E. Gent and the editors and anonymous referees of this journal. Arman Grigorian and Andreas Wimmer offered important conceptual input at the initial stage of this project. We are also grateful to Seraina Rüegger for coordinating the collection of the TEK data, which builds on her coding efforts and that of several other coders, including Nils-Christian Bormann, Manuel Vogt, Michael Bürge, Omar Kassab, and Charlotte Fidler. Additionally, Philipp Hunziker provided excellent assistance with calculations of the key variables and data management. Cederman and Salehyan acknowledge financial support from the Swiss Network of International Studies (SNIS). Gleditsch acknowledges support from the Research Council of Norway (1804410/V10). The online appendix is available at www.journals.cambridge.org/ino2013005.