  We investigate structural features and processes associated with the onset of
systemic conflict using an approach which integrates complex systems theory
with network modeling and analysis. We present a signed network model of
cooperation and conflict dynamics in the context of international relations
between states. The model evolves ties between nodes under the influence of a
structural balance force and a dyad-specific force. Model simulations exhibit a
sharp bifurcation from peace to systemic war as structural balance pressures
increase, a bistable regime in which both peace and war stable equilibria
exist, and a hysteretic reverse bifurcation from war to peace. We show how the
analytical expression we derive for the peace-to-war bifurcation condition
implies that polarized network structure increases susceptibility to systemic
war. We develop a framework for identifying patterns of relationship
perturbations that are most destabilizing and apply it to the network of
European great powers before World War I. We also show that the model exhibits
critical slowing down, in which perturbations to the peace equilibrium take
longer to decay as the system draws closer to the bifurcation. We discuss how
our results relate to international relations theories on the causes and
catalysts of systemic war.
