Firing Line

Kevin Lewis

November 14, 2022

Does the Bomb Really Embolden? Revisiting the Statistical Evidence for the Nuclear Emboldenment Thesis
Kyungwon Suh
Journal of Conflict Resolution, forthcoming 


This paper revisits the latest statistical evidence for the nuclear emboldenment thesis -- nuclear-armed states are more likely to initiate military aggression than non-nuclear states -- from (Bell and Miller 2015). If correct, their findings have important theoretical and policy implications regarding the effect of nuclear proliferation on international conflict. This paper shows, however, that Bell and Miller's findings heavily rely on two important components of their statistical analysis: (1) using all state dyad observations, and (2) employing pooled regression models to analyze time-series-cross-sectional (TSCS) data. I argue that those components are based on questionable assumptions on heterogeneity in their dataset. Based on alternative strategies dealing with heterogeneity in dyadic data, my reanalysis shows that the emboldening effect of nuclear weapons is not as robust as originally claimed. Instead, I find the robust deterrent effect of nuclear weapons: nuclear-armed states are less likely to be targeted in military disputes. These findings highlight the need for careful application of quantitative methods to produce a more robust understanding of nuclear issues.

Evidence of the unthinkable: Experimental wargaming at the nuclear threshold
Andrew Reddie & Bethany Goldblum
Journal of Peace Research, forthcoming 


Ongoing nuclear modernization programs in Russia, China, and the USA have reopened longstanding debates among scholars concerning whether tailored nuclear weapons are likely to have destabilizing consequences for international security. Without data to adjudicate this debate, however, these discussions have remained entirely theoretical. In this article, we introduce an experimental wargaming platform, SIGNAL, to quantify the effect of tailored nuclear capabilities on the nuclear threshold in a simulated environment. We then compare these results with a survey experiment using scenarios related to military basing, cyber operations, and nuclear threats from the wargame environment. While the survey experiments suggest that the presence of tailored nuclear capabilities increases the likelihood of conflict escalation, this trend diminishes in the wargaming context. Across both data-generating processes, we find support for the proposition that lower-yield nuclear weapons are used as a substitute for their higher-yield counterparts. These results have consequences for recent and ongoing policy debates concerning strategic posture and the future of arms control. This work also makes methodological contributions to the design and application of experimental wargaming for social science research, particularly for scenarios where data are limited or non-existent.

The reputational consequences of polarization for American foreign policy: Evidence from the US-UK bilateral relationship
Rachel Myrick
International Politics, October 2022, Pages 1004-1027 


How does partisan polarization in the United States affect foreign perceptions of its security commitments and global leadership? In a survey experiment fielded to 2000 adults in the United Kingdom, I demonstrate that priming respondents to think about US polarization negatively impacts their evaluations of the US-UK bilateral relationship. These impacts are stronger for the long-term, reputational consequences of polarization than for immediate security concerns. While foreign allies do not expect the United States to renege on existing security commitments, perceptions of extreme polarization make them less willing to engage in future partnerships with the United States and more skeptical of its global leadership. I find that these negative reputational consequences of polarization are driven by perceptions of preference-based, ideological polarization rather than identity-based, affective polarization. The results suggest that American allies anticipate that increasing divergence between the Republican and Democratic Party will create future uncertainty around US foreign policy.

The Effects of Combat Deployments on Veterans' Outcomes
Jesse Bruhn et al.
NBER Working Paper, November 2022 


As millions of soldiers deployed to Iraq or Afghanistan between 2001 and 2021, Veteran Affairs Disability Compensation payments quadrupled and the veteran suicide rate rose rapidly. We estimate causal effects of combat deployments on soldiers' well-being. To eliminate non-random selection into deployment, we leverage quasi-random assignment of newly recruited soldiers to units on staggered deployment cycles. Deployments increase injuries, combat deaths, and disability compensation, but we find limited evidence that they affect suicide, deaths of despair, financial health, incarceration, or education. More dangerous deployments have similarly limited effects. Our estimates suggest that deployment cannot explain either the recent rise in disability payments, which is more likely driven by policy changes, or the surge in noncombat deaths, which is better explained by shifts in observable characteristics of soldiers.

Cheap Tweets?: Crisis Signaling in the Age of Twitter
Benjamin Harris & Erik Lin-Greenberg
MIT Working Paper, September 2022 


World leaders are increasingly turning to social media as a medium for engaging in crisis signaling. This raises important questions about the effects of emerging communication technologies on international politics. In particular, do policymakers perceive threats issued via social media as more or less credible than those issued through traditional channels such as official government statements? Using original parallel survey experiments fielded both on a unique cross-national sample of foreign policy experts in the United States, India, and Singapore and on a U.S. public sample, we find that Tweet-issued threats are perceived as slightly less credible than identical threats issued through official statements. This project extends work on crisis signaling and the domestic politics of international relations by taking into account increasingly used emerging technologies.

How Much Risk Should the United States Run in the South China Sea?
Taylor Fravel & Charles Glaser
International Security, Fall 2022, Pages 88-134 


How strenuously, and at what risk, should the United States resist China's efforts to dominate the South China Sea? An identification of three options along a continuum-from increased resistance to China's assertive policies on one end to a partial South China Sea retrenchment on the other, with current U.S. policy in the middle-captures the choices facing the United States. An analysis of China's claims and behavior in the South China Sea and of the threat that China poses to U.S. interests concludes that the United States' best option is to maintain its current level of resistance to China's efforts to dominate the South China Sea. China has been cautious in pursuing its goals, which makes the risks of current policy acceptable. Because U.S. security interests are quite limited, a significantly firmer policy, which would generate an increased risk of a high-intensity war with China, is unwarranted. If future China's actions indicate its determination has significantly increased, the United State should, reluctantly, end its military resistance to Chinese pursuit of peacetime control of the South China Sea and adopt a policy of partial South China Sea retrenchment.

Military Culture and Institutional Trust: Evidence from Conscription Reforms in Europe
Vincenzo Bove, Riccardo Di Leo & Marco Giani
American Journal of Political Science, forthcoming


Does military conscription reduce the distance between the ordinary citizen and the state? Decades after its abolition, numerous European policy makers from across the political spectrum advocate the reintroduction of conscription to foster civic virtues, despite a lack of empirical evidence in this respect. Leveraging quasi-random variation in conscription reforms across 15 European countries, we find that cohorts of men drafted just before its abolition display significantly and substantially lower institutional trust than cohorts of men who were just exempted. At the same time, ending conscription had no effect on institutional trust among women from comparable cohorts. Results are neither driven by more favorable attitudes toward the government, nor by educational choices. Instead, this civil-military gap unfolds through the formation of a homogeneous community with uniform values. We argue that reintroducing a compulsory military service may not produce the effects anticipated by its advocates.

Long-Term Change in Conflict Attitudes: A Dynamic Perspective
Alon Yakter & Liran Harsgor
British Journal of Political Science, forthcoming 


A large literature examines how citizens in violent conflicts react to the conflict's events, particularly violent escalations. Nevertheless, the temporal nature of these attitudinal changes remains under-studied. We suggest that popular reactions to greater violence are typically immediate but brief, indicating short-term emotional responses to physical threats. Over the longer term, however, public opinion is more commonly shaped by non-violent events signaling the adversary's perceived intentions, reflecting slower but deeper belief-updating processes. We support this argument using dynamic analyses of comprehensive monthly data from Israel spanning two full decades (2001-20). Rather than violence levels, we find that long-term changes in Jewish attitudes on the Israeli-Palestinian conflict follow non-violent events implying Palestinian preferences, particularly failed negotiations and out-group leadership changes. Our findings underscore the importance of public opinion's temporal dynamics and show that non-violent events, which are often overlooked in the literature, play a prominent role in shaping long-term attitudes in conflictual contexts.

Dangerous Changes: When Military Innovation Harms Combat Effectiveness
Kendrick Kuo
International Security, Fall 2022, Pages 48-87 


Prevailing wisdom suggests that innovation dramatically enhances the effectiveness of a state's armed forces. But self-defeating innovation is more likely to occur when a military service's growing security commitments outstrip shrinking resources. This wide commitment-resource gap pressures the service to make desperate gambles on new capabilities to meet overly ambitious goals while cannibalizing traditional capabilities before beliefs about the effectiveness of new ones are justified. Doing so increases the chances that when wartime comes, the service will discover that the new capability cannot alone accomplish assigned missions, and that neglecting traditional capabilities produces vulnerabilities that the enemy can exploit. To probe this argument's causal logic, a case study examines British armor innovation in the interwar period and its impact on the British Army's poor performance in the North African campaign during World War II. The findings suggest that placing big bets on new capabilities comes with significant risks because what is lost in an innovation process may be as important as what is created. The perils of innovation deserve attention, not just its promises.

Gone with the wind: The consequences of US drone strikes in Pakistan
Rafat Mahmood & Michael Jetter
Economic Journal, forthcoming 


Employing day-to-day wind conditions as an identification strategy, we explore the consequences of the 420 US drone strikes in Pakistan between 2006 and 2016. Results suggest drone strikes encourage terrorism over the upcoming days and weeks, causing up to 19 per cent of all terror attacks with more than 3,000 terror deaths in Pakistan during that period. Studying a leading Pakistani newspaper, we identify a polarised response to drone strikes as negative emotions and anger, but also positive emotions, in drone-related articles increase. Finally, anti-US protests and online searches exhibiting radical Islamist concepts increase as a consequence of drone strikes.

A Friend Like Me: The Effect of IO Membership on State Preferences
Naomi Egel & Nina Obermeier
Journal of Politics, forthcoming 


Do international organizations (IOs) have an independent effect on state preferences? Despite the importance of this question in the International Relations literature, isolating the causal effect of IO membership has proven difficult due to endogeneity concerns. This research note offers a novel empirical approach to identifying the causal effect of shared membership in IOs on member state preferences. We exploit the fact that states joining the European Union (EU) obtain automatic membership in several other IOs through the EU's membership in these organizations. We then use a difference-in-differences strategy to estimate the effect of automatic membership in IOs on preference similarity with other members versus preference similarity with non-members. We demonstrate that shared IO membership leads to an increase in preference similarity. This approach offers a useful way to disentangle the effect of IO membership from selection effects that lead states to join IOs.

Looking Like a Winner: Leader Narcissism and War Duration
John Harden
Journal of Conflict Resolution, forthcoming 


Can an individual impact a phenomenon as overwhelming and complex as war? Do leaders impact interstate war dynamics? Leaders high in grandiose narcissism focus their efforts on maintaining their inflated self-image during war by striving desperately for victory. While most leaders sacrifice their historical image for state interests, more narcissistic leaders only exit wars if they "win", or overcome threats to their self-image. Narcissists essentially ignore revealed information and create deadlock to avoid looking like losers. In other words, narcissistic leaders encourage us to look beyond traditional rationalist models of wartime dynamics. This paper analyzes United States' interstate war duration from 1897 to 2007 and finds support for the argument that more narcissistic United States presidents extend war duration. This paper also compares Eisenhower's handling of the Korean War and Nixon's handling of the Vietnam War as an illustrative probe of causal mechanisms.


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