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Not at all! I appreciate your engagement. Addressing selection effect is hard, and your comments make me think about what I could have done differently and what future studies can do. I see my paper as a first step toward this important question, but definitely not the final word on ED.

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I expect that with more data on other aspects of conflict, security environment, etc. we will be able to test our theories from novel angles. It is possible that future studies would find that nuclear superiority matters in different contexts, therefore I need to qualify my conclusion!

Regarding your broad point, yes, confict (or MID) initiation may be not the only thing extended "deterrence" wants to deter; but it's an important one (and arguably the most basic one), and my approach is that if we did not find evidence in that context, that says something about the broad claim.

Multiple times, so I think that it's still useful as a measure of the security environment. And combined with other analyses (e.g., selection model estimation, Soviet alliance formation apttern), I think that the data suggests that the evidence for the selection argument is not strong.

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Thank you for the point. Yes, MID is not a perfect way of measuring the broad security environment; in that sense, that evidence alone may be not strong enough to challenge the selection effect claim. That said, MID is a widely used indicator and has been externally "audited" ...

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Thank you, Brian! This means a lot to me!!

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Special thank you to Giles David Arceneaux, Do Young Lee, and Iain Henry for constructive feedback!

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Of course, they do not rule out the possibility that nuclear superiority may generate other benefits; but US policymakers would need a serious net assessment regarding the costs and benefits of a potential nuclear buildup across several different contexts.

Taken together, these findings demonstrate the need to reconsider the idea that nuclear superiority would strengthen peacetime deterrence against nuclear-armed adversaries.

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Nuclear balance and the initiation of nuclear crises: Does superiority matter?

My previous JPR paper, which tests the deterrent effect of nuclear superiority in a direct deterrence context, also found no evidence that nuclear superiority reduces the risk of a crisis initiated by another nuclear-armed state. doi.org/10.1177/0022...

doi.org

Abstract. The nuclear competition school, an emerging theoretical perspective on the political effect of nuclear weapons, argues that a favorable nuclear b

Using five different indicators of nuclear balance, my analysis finds that across different model specifications, there is no strong evidence that a favorable nuclear balance reduces the risk that an ally of a superpower becomes a target of an MID initiated by another superpower.

This is a favorable empirical setting for the thesis. Why? Because the risk of nuclear escalation was perceived as serious between the US-led bloc and the USSR-led bloc. Those concerns were especially strong during the Cold War. This makes nuclear balance especially relevant.

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I tested this “superiority-credibility-thesis—the idea that nuclear superiority strengthens extended deterrence because it makes threats of nuclear retaliation credible—using data on superpower-led alliances during the Cold War.

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The idea that nuclear superiority strengthens deterrence is not new; scholars have debated about it since 1949. And experts have claimed that nuclear superiority is particularly useful for extended deterrence, where concerns over credibility are especially strong.

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Jeffrey Lewis @armscontrolwonk.bsky.social · 24/12/2025

New START has expired; China is building up its nuclear arsenal. Calls to expand U.S. nuclear forces are growing. Proposals vary, but the underlying message is the same: the United States needs to maintain a nuclear advantage over adversaries to strengthen deterrence.

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Reposted by Kyungwon Suh

The New START treaty doesn't expire until February 5. Stationing Oreshnik in Belarus prior to it's expiration is one last violation of the treaty. 🧵

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Reposted by Kyungwon Suh

Adam Mount @ajmount.com · 28/10/2025

1. Crises, acquisitions, and policy all suggest that conventional weapons are taking on a larger role deterring nuclear use. My new article in @intsecurity.bsky.social examines why US officials would consider conventional options when they have nuclear options available and how they might use them.

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Reposted by Kyungwon Suh

Giorgio Malet @giorgiomalet.bsky.social · 21/10/2025

🚨 New article out in @jeppjournal.bsky.social with @svenhegewald.bsky.social “The changing geography of support for European integration in the shadow of the Ukraine war." How did Russia’s invasion reshape public support for EU policies? www.tandfonline.com/doi/full/10....

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Robert Colby @rkdcolby86.bsky.social · 21/08/2025

Fantastic resource for historians: a spreadsheet of NARA's digitized microfilm, with links to the files in the Archives catalog. May it help you as much as it has helped me. www.archives.gov/files/colleg...

archives.gov

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In sum: during crises, allies want to see credible, costly signals, and the United States has a range of military and diplomatic toolkits. Insights from costly signaling theories apply well to alliance reassurance.

Interestingly, all three effective tools had substantively similar effects. Military signals (conventional or nuclear) and public remarks seem substitutable—in contrast to claims that actions always outweigh words. But diplomatic overtures towards adversary fail to reassure.

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I examined how each U.S. policy response influences the perceived safety of South Korea from DPRK aggression—a direct measure of reassurance. The results: Conventional and nuclear signals work; Public statements of support also work; but Diplomatic overtures do NOT work.

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To address this gap, I fielded a survey experiment with South Korean citizens during a hypothetical North Korea–ROK–U.S. crisis. I tested four tools: conventional signals, nuclear signals, statements of support, and diplomatic overtures to the adversary.

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So what reassures allies in times of crisis? Most research examines reassurance success indirectly (e.g., allies don’t proliferate, so they are reassured). Policy tools for reassurance are many, but empirical evidence is thin.

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In fact, reassurance may matter most when allies face imminent threats during crises—precisely when allies want their patron’s support most. Failure to reassure at those critical moments could have lasting impacts.

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Skeptics may wonder if Washington will care about reassuring its allies (given its recent behavior). But I find it unlikely that the U.S. would sit idle if a core ally is caught in a serious crisis.

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When alliances serve your strategic interests, reassuring allies is key to managing them well. So it's important to understand what tools help a patron like the U.S. actually reassure its allies.

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In sum: great power shocks generate ambitious bids for independence—but these moments shape the timing of secession more than the outcomes. Hope this piece adds to growing efforts to connect international and domestic dynamics of state birth.

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Using a global dataset of secessionist movements (1900–2011), we find that great power shocks strongly increase the onset of secessionist movements, but have little effect on their success. The results are robust across different measures of shocks and model specifications.

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But here’s the catch: while secessionist onsets spike, their success rate doesn’t. New movements often emerge too quickly, lack capacity, and collapse once metropoles recover. In other words, sudden great power shocks create secessionist "bubbles."

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Our paper shows how great power shocks—like the end of World War I, World War II, or the Cold War—produce bursts of secessionist movements across the globe. Why? Because they temporarily loosen the grip of powerful metropoles and create windows of opportunity.

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Most research on secession focuses on domestic factors—ethnic divisions, economic grievances, or institutional legacies. That makes sense: secession always arises from local contexts. But it is also embedded in broader international dynamics.

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Hegemonic shocks and patterns of secession

Interested in how major geopolitical shifts shape the dynamics of state birth? Check out our new article on great power shocks and global patterns of secessionist movements (with Ryan Griffiths and @seva.bsky.social). Link: doi.org/10.1080/0305... A short thread 🧵

doi.org

Studies of secession typically focus on domestic factors that produce independence movements, such as the role of ethnic divides or the concentration of material resources. But motivations for sece...