Abstract The post-Cold War decline in violent conflict has given way to rising instability both within and between states. While many attribute this shift to intensified great power competition, we argue that nationalist geopolitics, manifested through conflict driven by grievances reflecting the political exclusion of ethnic groups and their kin, offer a more accurate explanation. We explain how endogenous and exogenous factors weakened the liberal international order, which allowed ethnic nationalism to resurge in the early twenty-first century. This erosion of broader liberal norms, particularly what we call liberal backsliding, has started to undermine the inclusive policies that ultimately helped to stabilize the post-Cold War peace. Using newly updated global data on ethnic power relations (1946–2023), we document a reversal of inclusionary trends that began in the early 2010s. These findings challenge power-centric explanations of global instability and highlight how liberal institutional erosion, particularly in the domain of ethnic inclusion, creates fertile ground for identity-based violence. The return of nationalist geopolitics is thus rooted in not only shifting power relations but also retreating institutional safeguards.
Abstract Fifty years ago, the founders of this journal hoped that its creation would help revitalize the academic study of international security. Their ambitions have been fulfilled: International Security is now one of the most widely cited journals in the field of international relations and there is a robust community of scholars studying different aspects of the subject. The contents of the journal constantly evolve in response to world events, new scholarly developments, and its contributors’ particular interests, but it remains a vital resource for scholars and students alike. By facilitating active debates on important scholarly questions, International Security and other academic journals help educate each new cohort and contribute to robust discussions of critical policy questions.
Abstract Why do great powers believe it is necessary to have nuclear first-use options? What explains the different types of first-use options in the nuclear force postures of Russia and the United States? Why did China not develop a first-use option in the post-Cold War era? Existing literature focuses on whether great power nuclear strategies should entrench mutually assured destruction or compete for superiority, but it does not fully explain variation in first-use options. We compare the approaches to first use in the nuclear strategies of China, Russia, and the United States. Each of these great powers has different plans for both pursuing limited conflict objectives and countering conventional and geographic vulnerabilities, regime threats, and threats to allies, as well as different beliefs about damage limitation. Acute conventional and geographic vulnerabilities explain Russia's first-use options, which are optimized for state survival. Despite speculation that China might use nuclear weapons first to compel reunification with Taiwan, China has weak reasons to do so because it prefers non-nuclear means to achieve this objective. In contrast, the United States maintains options for first use, largely because of its extended deterrence commitments to allies and beliefs about damage limitation. These different approaches could fuel nuclear escalation in a conflict scenario.
Abstract Since the United States and the Soviet Union acquired the bomb in the 1940s, the common wisdom has been that each new proliferator would trigger its regional rivals and competitors to follow suit. Yet the incidence of such reactive proliferation is low. Scholars typically attribute this gap between expectation and reality to resource constraints and potential backlash from powerful allies and adversaries. These factors, however, only focus on the cost of nuclear pursuit. We focus on the other side of the equation, the cost of nuclear restraint or not pursuing the bomb, which derives from a state's assessments of the degree of nuclear threat that a rival poses. States are most likely to reactively proliferate when a proliferating rival has extensive aims and inferior conventional capabilities, factors that combine to make nuclear restraint costlier than pursuing the bomb. We demonstrate this theoretical insight's validity using interviews and new archival evidence pertaining to India's divergent assessments of China and Pakistan as nuclear threats. Our findings address the long-standing puzzle of why India did not pursue nuclear weapons in response to China's rapid nuclearization in the 1960s but acquired them in the late 1980s in response to Pakistan's acquisition.
Abstract The possibility that China might use military force to try to reunify with Taiwan increasingly worries analysts, especially as China expands its military investments and the political relationship between China and Taiwan deteriorates. Much of the military analysis of the relationship focuses on invasion scenarios, but some analysts suggest that a blockade is a less risky way for China to compel Taiwan to capitulate. This article points out some undesirable features of a traditional blockade in which China tries to interdict shipping approaching Taiwan, particularly by deploying a surface fleet and submarines. We built a Monte Carlo simulation model of an alternative Chinese concept of blockade operations using standoff missile strikes on ports to diminish cargo throughput to Taiwan. The military campaign analysis results suggest that China likely can substantially suppress Taiwan's trade, at relatively low escalation risk, without depleting China's scarce and expensive fleet. We discuss reasons why even militarily successful blockades have rarely achieved all their political goals, and we offer suggestions for Taiwan to build resilience and thereby reduce the probability of this potentially militarily effective concept of blockade operations.
Abstract The security dilemma is one of the most famous concepts in international politics. Yet questions remain about its causes and consequences. Specifically: How often are great powers under the security dilemma? How do they behave when they are under the security dilemma? This article offers a structural realist theory of the security dilemma to answer these questions. The central argument is that great powers are always under the security dilemma, and this almost invariably causes them to compete with one another more or less intensely for the means to security. This understanding is in stark contrast to the conventional view, captured by offense-defense theory, which finds that there are various conditions under which great powers can escape from under the security dilemma or cooperate in spite of it. An analysis of the logic of the two theories and a review of the historical record from 1871 to 1990 demonstrate that structural realism offers a better understanding of the security dilemma than offense-defense theory.
Abstract What explains success and failure in naval warfare? Most political science research on military effectiveness focuses on land combat, often overlooking how behavior shapes outcomes at sea. This article uses a paired comparison of two World War II naval battles—Savo Island and Cape Saint George—to examine how material and nonmaterial factors interact in maritime conflict. In both battles, U.S. forces held significant material and technological advantages, yet they suffered a catastrophic defeat in the former and achieved a lopsided victory in the latter. The decisive difference, we argue, lay in commanders’ behavioral choices, organizational structure, and crew proficiency in using technology under stress. Using case study comparison and counterfactual analysis, we demonstrate how similar material conditions produced dramatically different outcomes as a result of variation in nonmaterial performance. These findings suggest that naval combat is more sensitive to human factors than prevailing materialist assessments acknowledge. As U.S.-China competition intensifies in the Western Pacific, our analysis calls for greater attention to training, leadership, and doctrine when evaluating the implications of China's growing material power. Naval warfare is a deeply social process, and understanding its outcomes requires integrating human behavior with technological and material analysis.
Abstract This article is the first to explore the limitations of artificial intelligence in strategic decision-making and in preventing strategic surprise. Using well-known cases, it examines repeated difficulties involved in the collection, analysis, and dissemination of intelligence. Given collection challenges, corrupted data, legal limitations, classification barriers, and spoofing by adversarial AI systems, the article shows that adequate data to avoid surprise are often unavailable. Nor will AI eliminate the dangers of misapprehending information or the politicization of intelligence. The article then considers the theoretical limitations on the ability of computers of any level of power to predict the future. The future is random; any system in a given state can produce multiple future states. Consequently, even in a closed laboratory system, the ability to predict is subject to error and degrades rapidly over time. Unavoidable observational error, imprecision, and incompleteness create further difficulty. In strategic decision-making, these difficulties are compounded. AI will enhance strategic planning and improve short-term political forecasting within a margin of error, but it cannot be relied on for judgment, and it will not eliminate strategic surprises.
Abstract Right-wing populist leaders often seem to love soldiers (especially fallen ones) and the trappings of military life. But their love affair with the military rarely endures. This article explains this seeming paradox through the political logic of populism. Romanticizing and mythologizing the military solves a political problem for populists: how to mobilize people power without actually granting power to the people. Soldiers who willingly risk their lives for the nation serve as a model for an obedient public that should similarly march into the political battlefield on behalf of the populist leader. Dead soldiers cannot object when a populist leader exploits their memory. Populists understand that an independent, professional military is always at least a latent threat to their political ambitions. Once populists have bent other institutions to their will, they seek to control the military, erode its autonomy and professionalism, and transform it into a realm of loyalists. If the military resists, populists undermine public trust in it to facilitate taking it over. The article explores these dynamics in five case studies: Brazil under Bolsonaro; India under Modi; Poland under the Law and Justice Party; Turkey under Erdoğan; and the United States under Trump.
Abstract U.S. policy elites regularly claim that local populations welcome U.S. military intervention on their territory, which implies a powerful moral justification for war. Does the consent of the “intervened population” affect U.S. public support for military intervention? A large literature shows that U.S. support for war follows cost-benefit calculations. In this view, ordinary Americans are prudent, not principled, about war—specifically, they support low-cost interventions that are likely to succeed. Yet our conjoint survey experiment finds that American respondents do take a moral position regarding military intervention. In the experiment, we asked 3,360 U.S. citizens to evaluate ten hypothetical military intervention scenarios with attributes that we varied randomly. The results show that local consent significantly increases support for war on average, even when the intervention is predicted to be costless. This finding is consistent with the anti-paternalist position that using force for the benefit of others requires their consent as a matter of principle. Our study contributes to a recalibration of the roles of principled and prudential considerations in U.S. support for war. The importance of consent and the principled logic behind its effect on support for military intervention suggest that policy elites concerned with the democratic legitimacy of U.S. wars should identify the actual views of the population where the United States militarily intervenes.
Abstract Artificial intelligence (AI) has the potential to automate key tasks in the life cycle of a cyber operation. Many have predicted that AI will revolutionize cyber conflict by enabling offense automation for faster, stealthier, and more damaging attacks. But the revolution has not happened, even though highly capable AI models have been available for several years. This article explains why: There is a gap between defense and offense when it comes to the limits on what AI can do. Cyber offense requires creative deception to burrow into systems and produce desired effects before being discovered. Cyber defense, by contrast, strives to detect such intrusions before they cause harm. AI models struggle with the creativity and deception necessary for offensive operations, but they excel at the pattern recognition that is key for defensive operations. I show that this relative advantage of defensive tasks increases as the stakes increase. I test this theory against experimental and in-the-wild evidence of AI automation in cyber conflict. States that invest in defense automation will likely enjoy a growing advantage over those that prioritize investing in offense automation. Rather than heralding a revolution, AI automation is likely to further tame cyber conflict. Highly skilled human operators, not AI, will be necessary to avoid being detected by AI-empowered defenders.
This article identifies key differences between mainstream and Iraq-based understandings of Islamic State (ISIS) and how it rose to power in Iraq. The conventional wisdom in English-language discourses focuses on the group's organizational capabilities, particularly its military capacity, ideology, propaganda, and governance/state-building apparatus. Iraqi discourses suggest that in addition to these capabilities, the state opponents of ISIS enabled the group's growth because they benefited from its violence. The differences between these two broad narratives about ISIS matter because they reveal what is generally unsayable in mainstream discourses about the drivers of terrorism, which is that terrorist groups can reproduce through and alongside state power rather than in simple opposition to it. We conducted more than sixty in-depth, semi-structured interviews across Iraq with Iraqi and Western security analysts, journalists, humanitarian workers, and diplomats. Our interlocutors suggested that state actors had facilitated ISIS, at least at times. We argue that this facilitation is an example of what Michael Taussig refers to as a “public secret”—something that experts widely discuss but seldom document. The Iraq-based view that we detail suggests that states maintain power by enabling, and profiting from, unpredictable and plausibly deniable violence in the periphery—something that ISIS supplied in abundance. We argue that by obscuring how states can help make terrorist violence possible, mainstream understandings of terrorism create space for groups like ISIS to emerge in the future.
How has the balance of power shifted in maritime East Asia, and what does this change mean for the U.S.-China military competition in the region? We examine these questions by focusing on a central pillar of U.S. military might—land-based air power—in the context of a war over Taiwan. We create a new, unclassified, and transparent model of a Taiwan conflict, which allows users to explore multiple scenarios, alternative U.S. basing options, various People's Liberation Army attack strategies, and a range of potential U.S. defensive enhancements to see how those alternatives influence outcomes. We find that: (1) the United States' current approach to defend Taiwan exposes U.S. forces to significant risk of catastrophic defeat; (2) the U.S. Air Force's answer to this problem is both unlikely to work and escalatory; and (3) a combination of hardening air bases and enhancing missile defenses and local jamming at U.S. facilities is a better option. More broadly, U.S. national security policy toward China approaches an inflection point. The United States can lean in and significantly enhance the resilience of its forces in East Asia; lean back and rely more on instruments of military power that are less vulnerable to China's regional defense systems; or reconsider its broader geopolitical goals in the region. The current path, seeking to deter Chinese attacks with a vulnerable forward-based military posture, courts disaster.
How do U.S. security clients cope with the United States’ strategic demands to take actions that conflict with their political or economic interests? Much of the literature on intra-alliance politics explains clients’ decisions to accept or reject their patron’s demands. This article theorizes demand evasion as an option for a U.S. security client confronted with costly strategic requests from its patron. Demand evasion occurs when the client avoids answering the security patron’s repeated demand on a strategic issue without provoking the patron’s punishment. There are three methods of demand evasion: stalling, deferring, and slow-rolling. To decide how to respond to their patron’s strategic demand, U.S. security clients assess the patron’s internal coherence regarding the demand and the type of risks involved in the issue at stake. I illustrate the theory of demand evasion by examining how three U.S. treaty allies in the Indo-Pacific (Australia, Japan, and South Korea) responded to demands from different U.S. administrations. For U.S. leaders who seek immediate support from foreign allies, the theory is useful because it highlights the full range of options available to U.S. clients (i.e., acceptance, rejection, and evasion). Understanding why allies sometimes deliberately avoid making decisions on strategic issues is important for the United States as it seeks to confront its adversaries and protect its security interests.
U.S. space power has long been anchored to terrestrial geography. In the Cold War, the United States depended on a global network of facilities to track and communicate with military, intelligence, and civilian satellites. But it was difficult to secure access to foreign territories that were both in view of satellites as they passed overhead and politically reliable. Drawing on declassified Australian, British, and U.S. documents, this article details the largely invisible role of allies in U.S. space power. To mitigate the political challenges associated with basing space facilities in non-allied countries, the United States turned to Australia and Britain. But using allied territories was not risk free. Postcolonial independence movements threatened the security of tenure at key U.S. space tracking stations located in British territories in the Indian Ocean. Moreover, Australian concerns that U.S. space facilities were nuclear targets and violated Australia’s sovereignty created a domestic political uproar that strained the U.S.-Australia alliance. Political upheaval, even in allied states, was a significant vulnerability for U.S. space capabilities. Mitigating these political risks thus became a top U.S. foreign policy priority.
There has been a good deal of talk in recent years about the “rules-based international order”—the system of laws, agreements, principles, and institutions that, many observers say, lay at the heart of the international system that came into being after World War II. It is often argued that maintaining the rules-based order—and extending it if possible—should be a fundamental goal not just for the United States but for Western countries more generally. Those liberal internationalist arguments are supported by a number of historical claims: about how the rules-based order came into being and about the role played by key institutions, such as the North Atlantic Treaty Organization and the Bretton Woods monetary system. Those claims are examined here. The basic finding is that many common arguments in this area are not supported by the historical evidence. That finding serves as a kind of springboard for thinking about whether there are any viable alternatives to the sort of policy the liberal internationalists have called for. The argument here is that there are viable alternatives—alternatives based on certain traditional ideas about how foreign policy should be conducted.
Some academic literature and U.S. policy documents suggest that conventional deterrence is weaker than nuclear deterrence. But recent developments in U.S. policy suggest that conventional forces are assuming a larger role in deterring limited nuclear use. This article explores why and how U.S. officials may turn to conventional weapons to deter a nuclear attack. As conventional weapons are becoming increasingly capable of producing strategic effects in response to a nuclear attack, U.S. officials may be more likely to consider conventional deterrence as a credible option to deter those attacks. In some cases, U.S. officials are likely to prefer conventional options to avoid the costs, risks, and uncertainty of nuclear threats. To test the theory, the article presents the results of a series of individual, scenario-based “tabletop interviews” with former senior U.S. officials who might plausibly have been consulted on a decision about how to deter a North Korean nuclear attack. The results demonstrate that U.S. officials increasingly consider conventional deterrence of nuclear use to be a viable and valuable capability.
