| dc.description.abstract | How do non-nuclear allies of the United States bolster deterrence even as they rely on the United States and its nuclear umbrella for security? How do they exercise agency in operationalizing the deterrence extended to them by the United States against their nuclear-armed adversaries? Although the existing literature offers valuable insights into the measures the United States employs to signal commitment and enhance the credibility of its security guarantees, it has paid far less attention to the role of allies themselves. This dissertation addresses that gap by introducing allied integration theory, a new framework for understanding allies’ incentives and choices. The theory explains and predicts variation in allies’ peacetime military postures. I first develop a typology of four ideal types, each reflecting allies’ different choices regarding capabilities, doctrine, tolerance for escalation risk, and integration with U.S. forces, including U.S. nuclear forces. I then argue that allies’ decisions are shaped primarily by their threat environment. Specifically, I highlight two key factors: the threat of strikes (conventional, WMD, or nuclear) and the threat of invasion from their adversaries. I then test the theory through two pairs of comparative case studies. The first pair examines Japan and South Korea in the post-Cold War period; the second compares West Germany and Norway, two frontline states of NATO, during the later Cold War (1970s-1980s). This research design allows for examining both within-case and cross-case variation while holding constant many potential confounders within each pair. Drawing on extensive fieldwork, elite interviews, foreign-language sources, U.S. archival materials, and secondary sources, I analyze how each ally made key decisions on their postures and evaluate the performance of allied integration theory. The findings contribute to the broader debates on alliance politics in the nuclear era and the interplay between conventional and nuclear domains. The research also offers practical insights for addressing growing security challenges faced by U.S.-led alliances amid intensifying geopolitical competition with multiple nuclear-armed adversaries. | |
