Joseph J. Ruggiero

The preventive motive for war arises because states cannot commit to limit the use of their growing power. This commitment problem can lead to war when there are not enough resources available today to compensate the declining state for their expected losses. In this article, we show how capital markets affect preventive war incentives by introducing a profit-maximizing bond market to the canonical bargaining model of war. We find that the nature of the power shift and fundamentals of the market for debt interact to determine when a preventive motive is more likely to lead to war. Two main results show that (1) less probable but more extreme power shifts are most dangerous and (2) unlike the direct effect of interest rates on the cost of war, higher interest on sovereign debt makes war more likely. We present evidence for the latter effect by extending Lemke's (2003) study of preventive war for major-power dyads between 1816 and 1992.

Why do some conflicts escalate to global war, while others stay contained? At its core, the size of a war, as well as the incentive to start one, depends on expectations about who will join. Those expectations are, in turn, fundamentally shaped by political alignments and economic integration. I provide a formal model of conflict that accounts for these factors. Using data on international disputes from 1816-2014, I estimate the effect of economic networks and power asymmetries on the incentives for conflict. The results suggest (1) network spillovers pacify potential joiners, reducing the scale of war and consequently triggering more attacks, and (2) countries bandwagon, causing a correlation between power inequality and the expected size of war in equilibrium. Counterfactuals show that China is becoming less willing to go to war over Taiwan, as they are more likely to face opposition from the U.S. and less likely to receive support from Russia.

Maintaining peace with adversaries can be costly, yet conflict models depict cooperation as a costless byproduct of not fighting. This article provides a formal model where peace may be costly and countries compete over bargaining surplus. Against conventional wisdom, repeated interactions of patient countries can destabilize peace without power shifts, as countries may prefer to "rip off the bandage." The likelihood of war depends on fundamentals of the international order, including outcome persistence and the severity of competition. Even when cooperation is mutually beneficial, wars are inevitable in the long run due to a coordination problem induced by costly peace. Competition over favorable settlements does not directly instigate attacks, but it reduces the gains from peace while counterintuitively making war less likely. The article offers new systemic explanations for war, highlights the importance of institutional design in conflict resolution, and sheds light on which international orders fare well over time.

Social networks play an important role in distributive politics, yet social structure is rarely considered explicitly. We provide a formal model of elections in which candidates may offer excludable transfers to policy-motivated voters connected on a social network. By transparently incorporating group shares, homophily, and density of ties in a generative framework, our model facilitates systematic comparison across societies that vary on these underlying dimensions. In equilibrium, transfers are determined primarily by group shares and homophily, with density mattering only indirectly. Inequalities in provision of goods are driven by disproportionate targeting of minorities. Additionally, we consider heterogeneous information between candidates, clarifying the main role of density as a source of more precise information and demonstrating that homophily can endogenously produce in-group favoritism even when candidates are purely office-motivated. These results highlight the importance of aggregate social structure on targeted redistribution and suggest new directions for empirical studies of non-programmatic distribution.