Social-Cognitive identity is at partnership’s core. My dissertation explores an empirical puzzle of how and why did India and the United States form a strategic partnership in 2008. This bilateral relationship is puzzling because it appeared inconceivable to practitioners and theorists of international relations only a few years earlier. In this dissertation, I bracket the American side of the equation and instead focus on India. I then test the argument that domestic identities, composed of individual and social components, shape state foreign policies. I test this argument by employing a novel sequential, multimethod research design that combines discourse analysis and a traditional large-n survey in a single study. This research design consists of, first, using discourse analysis of India’s select popular textual sources, and then employing the thematic categories generated from the discourse analysis to design and conduct a large-n survey. This survey was conducted with a sample size of 804 respondents in two Indian cities using cluster sampling. The combination of these two data collection techniques produced the empirical findings. The social-cognitive identities of India defined the content and nature of the India-U.S. strategic partnership; variations in those identities generated variations in the different aspects of this partnership. The substantive aspects of the partnership analyzed in the dissertation relate to the growth of economic relations, the conclusion of civil (and not military) nuclear agreement, and the clear disagreement over climate change. Given its theoretical framework and multimethod approach, my dissertation makes three contributions to the field of International Relations: it establishes strong correlations between disparate empirical phenomena in valid and reliable manner, it demonstrates novel ways to combine different research techniques to analyze new substantive problems, and it increases confidence to explain and predict state foreign and security policies.