Domestic Politics and Prospect Theory in International Conflict: Explaining Japan’s War Decision in the 1904 Russo- Japanese War Steven B. Rothman, Ritsumeikan Asia Paciic University Abstract his project explains the Japanese decision for war against Russia in 1904 by applying theories of war involving the democratic process, the domestic and government interests, and prospect theory. he project demonstrates the limits of psychological variables to analyze or explain international decisions due to the political complexity and domestic and global context of decision-making. In particular, the project uses economic framing to proxy a gains domain and security frames to proxy the losses domain. Risk sensitivities and preference ordering of the domestic interests (military and common business persons) are consistent with prospect theory, while the political connections between domestic constituents and decision-makers provide an intervening inluence on the decision for war. he result suggests careful use of prospect theory and the importance of factors in addition to psychological ones when applied to international politics. Keywords: decision-making, international conlict, prospect theory, Russo-Japanese War Introduction his project demonstrates the importance of careful use of cognitive decision theories to illuminate international relations decisions. Despite scholars’ widespread and increasing use of psychological variables to explain international afairs, the complexity and context of international and other intervening conditions make psychological variables diicult to fully utilize in the international context. he essay examines the inluence of framing from diferent inluential actors in the Japanese decision to begin war with Russia. he essay shows that contextual variables interfere with cognitive decision biases and frames, thus reducing the inluence of psychological factors at the international level of decision- making. Asia Paciic World 2(2), Autumn 2011: 66–84 © Asia Paciic World doi:10.3167/apw.2011020206