national security

Foreign Affairs Essay – The Battle Over Blocking the Sun

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My colleague Scott Moore and I published an essay in Foreign Affairs that summarized some of the arguments that we make in our forthcoming law review article in the Harvard International Law Journal. The essay (with a title we did not love) is “The Battle Over Blocking the Sun: Why the World Needs Rules for Solar Geoengineering,” Foreign Affairs, Aug. 14, 2024. The argument is captured in the abstract to our much longer law review article, “Geoengineering Wars and Atmospheric Governance,” Harvard International Law Journal (forthcoming, 2025), which is here:

The increasingly harsh and unevenly distributed heat-related harms caused by climate change, together with the frustration over the collective inability to respond to the crisis, are likely to make unilateral geoengineering efforts increasingly attractive. Stratospheric aerosol injection (SAI) is a form of solar radiation modification that is effective, technically feasible, and within the financial means of many states and even non-state actors. Yet there are virtually no global governance structures in place to specifically regulate such activity, and existing international law would provide only weak constraints on unilateral SAI efforts. These features create incentives for unilateral action in what is known as “free driver” problem —few constraints on unilateral action that has low direct cost combined with immediate direct individual benefit and widely distributed risks and indirect costs.

There would be significant collateral environmental and climatic harms associated with SAI. That, coupled with the high risk of unilateral action, is reason enough for both caution and stronger governance. But another risk posed by any unilateral SAI effort—one that is underappreciated and under-theorized—is that of armed conflict. We explore how and why states would likely perceive the potential risks associated with unilateral SAI effort as constituting a threat to national security, and in the absence of adequate legal and institutional mechanisms to constrain such unilateral action, might well contemplate the use of force to defend against the perceived threat. The article explores and explains how and why the jus ad bellum regime is unlikely to prevent states from engaging in unauthorized use of force against unilateral SAI actors.

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Guest on Energy Policy Now! Podcast – Managing the Geopolitical Risks of Solar Geoengineering

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My colleague Scott Moore and I were guests on the Energy Now! Podcast, produced by the University of Pennsylvania’s Kleinman Center for Energy Policy, for an episode entitled “Navigating the Geopolitical Risks of Solar Geoengineering,” to discuss our law review article on this topic forthcoming in the Harvard International Law Journal, and shorter essay on the subject in Foreign Affairs.

Discussing “Eye in the Sky” from a Legal Perspective – Law and Film!

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In the latest episode of JIB/JAB-The Laws of War Podcast, I have a cross-posted episode in which I am the guest of Jonathan Hafetz on his Law and Film Podcast to discuss the film Eye in the Sky. It is a 2015 film likely known to most JIB/JAB listeners, about a joint British and American drone strike against al-Shabaab terrorists in Kenya, and which intelligently and engagingly explores the legal, ethical, philosophical, political, and strategic issues raised by the operation. We not only examine the film’s treatment of the legal issues implicated, including whether IHL should apply at all, and how the principles of distinction, necessity, proportionality, and precautions in attack are illustrated in the film, but we also explore the relationship between these principles and some of the ethical and strategic aspects of the decision-making in the film. We round out the conversation with a discussion of some other engaging films that similarly explore law in the context of armed conflict. I very much enjoyed the conversation!

Canada’s ‘Royal Prerogative’ Allows it to Wage War Without Parliamentary Approval

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(Published in The Conversation, Oct. 24, 2022).

Questions are being raised again about how the Canadian government makes decisions to use force or participate in armed conflicts, prompted by reports that special forces units of the Canadian Armed Forces were operating on the ground in Ukraine.

While ostensibly deployed strictly for “training purposes,” such involvement can lead to more direct engagement in an armed conflict.

The decision to engage in armed conflict is one of the most consequential decisions a government can make. Who is involved in the decision-making, and what conditions or principles govern that process? Even more importantly, how should these decisions be made?

As a recent report suggests, the Ukrainian deployment has rekindled interest in these questions on Parliament Hill. But there should be a broader public discussion and debate.

Most Canadians would be surprised to learn that the prime minister and the cabinet have a far more unfettered power under the so-called royal prerogative to take the country to war than most other western democracies.

Early limits on war-waging powers

The modern idea that the power of the executive branch to wage war should be limited can be traced back at least as far as the Glorious Revolution in 1688, when English parliament placed constraints on the king’s ability to raise and maintain an army.

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