Lawfare Daily: Oona Hathaway on the Collapse of Norms Against the Use of Force 

How the prohibition on the use of force is under pressure: kleight and context

Oona Hathaway traces the modern prohibition on war back to the Kellogg-Briand Pact and the UN Charter, arguing that the post-World War II legal order made conquest and gunboat diplomacy unlawful. This episode untangles how current events—U.S. threats and strikes, Russia's invasion of Ukraine, and China's maritime coercion—challenge that foundational norm and risk a more violent, unstable world.

Why the Kellogg-Briand Pact and UN Charter matter for the modern world order

The podcast explains why the Kellogg-Briand Pact's renunciation of war required a broad legal transformation. That prohibition underpins rules against conquest, threats, and coercive diplomacy, enabling trade, diplomacy, and international institutions to function without constant fear of seizure or occupation.

Legal tests: preemptive self-defense, collective defense, and the Caroline standard

Hathaway emphasizes that Article 51 of the UN Charter permits self-defense only after an armed attack or under a strict imminent-threat standard (the Caroline test). Preemptive or anticipatory strikes lack clear legal grounding unless imminence, necessity, and proportionality can be demonstrated to the international community.

When law meets power: why legal norms persist and why they unravel

The discussion rebuts the view that norms are irrelevant compared to power. Law both shapes and is shaped by power: states create legal expectations that alter interests, enabling durable trade and cooperation. But repeated violations, ambiguous rhetoric, and unilateral strikes erode credibility and encourage imitators.

Negotiating peace under coercion: duress, the Vienna Convention, and non-binding solutions

Hathaway explores the legal dilemma of negotiated settlements made under threat of force. Treaties concluded under duress are void under the Vienna Convention. Practically, many ceasefires or agreements may be non-binding, politically enforceable arrangements — as with the JCPOA model — supplemented by Security Council endorsements or on-the-ground guarantees.

What can be done: coalitions, middle powers, and renewed norm enforcement

The episode closes with a forward-looking argument: the system can survive only if more states — not just the United States — step up to defend legal norms. Europeans, middle powers, and coalition-building in the General Assembly can reinforce prohibitions on force and prevent a slide into spheres-of-influence geopolitics.

• Key takeaways: legal thresholds matter, threats corrode norms, non-binding agreements can be practical.
• Practical implication: multistate coalitions must act to sustain the rule-based international order.