The Saavedra Lamas Peace: How a Norm Complex Evolved and Crystallized to Eliminate War in the Americas

s After the Napoleonic Wars interstate war regularly occurred throughout the Western Hemisphere—until in matter of decades it disappeared. After the 1930s even low-level militarized interstate conflict became less frequent, shorter, and less severe over time. What explains the change in this specific region and historical jucture? We argue that leaders in the Americas identified territorial disputes and foreign intervention as interrelated problems that frequently caused the interstate war. In response, they developed a unique regional norm-complex that bundled together the norms of territorial integrity and non-intervention with the principle of peaceful conflict resolution. This norm complex emerged via Latin American entrepreneurship shortly after independence, cascaded with Pan-Americanism, and crystallized around the signature of the Saavedra Lamas Treaty in the early 1930s. We explain how, why, and when norm complexes develop. We then investigate the evolution and effects of the Latin American norm complex via statistics and within-case counterfactuals. We conclude that interstate war disappeared from the Americas with the acceptance and codification of this norm-complex.