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On April 6, 2017, the United States launched fifty-nine Tomahawk missiles against an air base in Syria, after evidence surfaced that Bashar Al-Assad’s regime had again used chemical weapons against its people. President Trump announced that the strikes were intended “to prevent and deter the spread and use of deadly chemical weapons.” But as of this Symposium’s publication, the United States has not articulated a formal legal justification for the strikes. Instead, it reportedly circulated a document that listed several case-specific considerations that, in its view, justified the use of force. Yet the global reaction was overwhelmingly positive. Many states openly supported the U.S. strikes; very few condemned them.

This Symposium uses that incident as a springboard for asking a more general and fundamental question about the jus ad bellum: how should we assess military interventions that lack Security Council authorization but are, or are claimed to be, taken for a public good? The public good might be halting an ongoing humanitarian crisis, supporting a people’s right to self-determination, deterring conduct that is widely believed to be unlawful, enabling the transfer of power after a democratically sound election, or helping to stabilize a “failing” state. The majority view is that such interventions are unlawful, unless they can be justified in self-defense or by the territorial state’s consent. As a practical matter, this means that they are often unlawful — or at least, legally dubious. Although some actors might try to justify them in defensive or consensual terms, such claims typically rely on legal theories that are controversial and not widely endorsed.


International Humanitarian Law | Law | Military, War, and Peace

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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.