No abstract

Historical institutionalism as an explicit tradition has largely remained on the sidelines in international security scholarship, with some exceptions. The chapter begins by reviewing the sources of resistance to the tradition in security studies. We then apply its analytical toolbox to two empirical realms at different levels of analysis: divergent regional security paths in East Asia and the Middle East; and the evolution of the nuclear non-proliferation regime. These cases show the utility of historical institutionalism in spanning sub-national, regional and international levels of analysis; its value for examining the role of critical junctures for evolving security arrangements; and its timely applicability beyond topical, geographical, and ontological foci that have been standard fare in security studies.

Since the advent of the nuclear age, scholars have sought to provide rationales behind decisions to pursue, forgo, or relinquish nuclear weapons programs. Security, status, cost, technical capabilities, and domestic considerations have played central roles in explaining those choices. Classical neorealism was once the conventional wisdom, advancing that relative power and the logic of self-help in an anarchic world drove states to nuclear weapons. Yet, the analysis of nuclear proliferation has evolved in accordance with broader debates in international relations theory in recent decades, including the incorporation of neoliberal institutionalist, constructivist, and domestic political perspectives. The end of the Cold War and the upheaval of international order in particular marked a watershed for the literature, with scholars challenging the dominant paradigm by examining the effects of institutions, norms, and identities. Those approaches, however, under-theorized—if not omitted altogether—the role of domestic political drivers in choices to acquire or abstain from acquiring from nuclear weapons. Such drivers provide filters that can be invaluable in explaining whether, when, and how state actors are susceptible to considerations of relative power, international institutions, and norms. More recently, scholars have deployed more sophisticated theoretical frameworks and diverse methodologies. The road ahead requires greater analytical flexibility, harnessing the utility of classical perspectives while adding enough nuance to increase explanatory power, greater attentiveness to the complex interaction among variables, and improved specification and operationalization amenable to rigorous testing, all with an eye toward enhancing both historical accuracy and predictive capabilities.

This paper examines the primary international firewall in place against the diffusion of nuclear weapons and related equipment, materials, and knowledge. It links the transformative moments of the nuclear non‐proliferation regime to select events. It posits these shocks either (i) revealed the presence of, or (ii) instigated fears about new or accelerated diffusion flows, with clear implications for nuclearization. By recasting the regime's evolution in this manner, the paper provides newfound insight as to the timing and character of change. It also reveals the considerable impact of diffusion processes beyond outcomes of diffusion and non‐diffusion, adding definition to the firewall concept.

This essay traces the evolution of the literature on the rationale behind states' pursuit of nuclear weapons, from classical neorealist explanations focusing on relative power to neoliberal institutionalist ones underlining the deterrent power of institutions and constructivist work on the impact of norms, status, and identities. We call attention to their contributions as well as their conceptual and empirical deficiencies and introduce an approach that links both nuclear ambition and nuclear restraint to models of domestic political survival. The inclusion of this previously overlooked independent variable harnesses the utility of extant approaches, allowing more effective weighing of the impact of other causal variables, while accounting for variation over time, across and within states. We take stock of more recent work employing quantitative and qualitative approaches and identify an agenda for advancing causal theories explaining why some states pursue nuclear weapons whereas others do not.