2026 Mike Lewis Memorial Forum: Would a Lower Threshold for the Use of Force Under International Law Make the World Safer?

The annual Mike Lewis Memorial Forum honors the life and legacy of Mike Lewis, a former naval aviator and leading scholar of international law. Mike wrote and spoke extensively on the use of force and the law of armed conflict and served on the Executive Committee of the Federalist Society’s International & National Security Law Practice Group. Mike passed away from cancer in 2015 at age 50. He was admired across ideological lines for both his scholarship and his generosity of spirit.
This year’s Forum will examine the law governing anticipatory self-defense and whether the traditional interpretation of international law adequately accounts for modern threats. This traditional view generally permits anticipatory self-defense only against an “imminent” threat. But that standard took shape in an era when threats moved at the speed of 19th-century naval vessels.

How should that requirement apply in an era of missiles, cyberattacks, and other threats capable of materializing rapidly? Critics argue that a strict imminence requirement leaves states unable to respond to serious threats before they fully materialize, and that the resulting gap between doctrine and state practice erodes confidence in international law. Defenders of the traditional standard counter that loosening it risks inviting states to invoke self-defense as a pretext for aggression.

The panel will consider whether international law should permit a broader range of anticipatory action against developing threats, what principles should govern such uses of force, and whether the U.N. Charter itself can be interpreted to accommodate them. More broadly, the discussion will explore how the law governing self-defense can respond to changing technologies and security challenges while continuing to constrain the use of force.

Featuring:

• Dr. Brian Cox, Senior Fellow, Macdonald-Laurier Institute
• Prof. John Yoo, Emanuel S. Heller Professor of Law, University of California at Berkeley; Senior Research Fellow, School of Civic Leadership, Civitas Institute, University of Texas at Austin; Nonresident Senior Fellow, American Enterprise Institute
• (Moderator) Vincent J. Vitkowsky, Fellow, National Security Institute, Antonin Scalia Law School, George Mason University

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As always, the Federalist Society takes no position on particular legal or public policy issues; all expressions of opinion are those of the speaker.