No democracy impact.
Chiba ’21 [Daina and Erik Gartzke; February 19; Associate Professor of Political Science in the Department of Government and Public Administration at the University of Macau, Ph.D in Political Science from Rice University, LL.M in Jurisprudence and International Relations from Hitotsubashi University; Professor of Political Science at the University of California, San Diego, PhD in Political Science from the University of Iowa; Office of Naval Research, “Make Two Democracies and Call Me in the Morning: Endogenous Regime Type and the Democratic Peace,” p. 1-44]
The democratic peace—the observation that democracies are less likely to fight each other than are other pairings of states—is one of the most widely acknowledged empirical regularities in international relations. Prominent scholars have even characterized the relationship as an empirical law (Levy 1988; Gleditsch 1992). The discovery of a special peace in liberal dyads stimulated enormous scholarly debate and led to, or reinforced, a number of policy initiatives by various governments and international organizations. Although a broad consensus has emerged among researchers regarding the empirical correlation between joint democracy and peace, disagreement remains as to its logical foundations. Numerous theories have been proposed to account for how democracy produces peace, if only dyadically (e.g., Russett 1993; Rummel 1996; Doyle 1997; Schultz 2001).
At the same time, peace appears likely to foster or maintain democracy (Thompson 1996; James, Solberg, andWolfson 1999). A vast swath of research in political science and economics proposes explanations for the origins of liberal government involving variables such as economic development (Lipset 1959; Burkhart and Lewis-Beck 1994; Przeworski et al. 2000; Acemoglu and Robinson 2006; Epstein et al. 2006) and inequality (Boix 2003), political interests (Downs 1957; Bueno de Mesquita et al. 2003), power hierarchies (Moore 1966; Lake 2009), third party inducements (Pevehouse 2005) or impositions (Peceny 1995; Meernik 1996), geography (Gleditsch 2002b), and natural resource endowments (Ross 2001), to list just a few examples. Each of these putative causes of democracy is also associated with various explanations for international conflict. Indeed, some as yet poorly defined set of canonical factors may contribute both to democracy and to peace, making it look as if the two variables are directly related, even if possibly they are not.
We seek to contribute to this literature, not by proposing yet another theory to explain how democracy vanquishes war, but by estimating the causal effect of joint democracy on the probability of militarized disputes using a quasi-experimental research design. We begin by noting that some of the common causes of democracy and peace may be unobservable, generating an endogenous relationship between the two. Theories of democracy and explanations for peace are at a formative state; it is not possible to utilize detailed, validated and widely accepted models of each of these processes to assess their interaction. Indeed, to a remarkable degree democracy and peace each remain poorly understood and weakly accounted for empirically, despite their central roles in international politics. We address the risk of spurious correlation by applying an instrumental variables approach. Having taken into account possible endogeneity between democracy and peace, we find that joint democracy does not have an independent pacifying effect on interstate conflict. Instead, our findings show that democratic countries are more likely to attack other democracies than are non-democracies. Our results call into question the large body of theory that has been proposed to account for the apparent pacifism of democratic dyads.