Mackinder Forum Seminar #63: Dr. Thomas Grant, “Geopolitics and International Law”

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On Sunday, August 14, 2022, 1:30-3:00 p.m. Eastern US Time, Dr. Thomas Grant addressed the Mackinder Forum Seminar on “Geopolitics and International Law.”  

ABSTRACT:  Geopolitics and international law might seem disconnected. Thomas Grant argues that the connections between them, however, run deep. International law—the law that applies among States in their international relations—exists in a particular geopolitical setting and achieves what efficacy it does, because geopolitics, at least for a time, has been congenial to legal rules and their observance.

International lawyers show little interest in geopolitics. Their indifference owes to nearly 80 years of relative stability and security in international relations. Moreover, as geopolitics seemed to recede, international law thrived. Between 1945 and the present—that is to say, since the last world-level breakdown of stability and security—international law grew into a dense system of rules and institutions, and these in turn came to support an apparatus of judges, arbitrators, advocates, advisers, teachers, and theoreticians. The cadres of international law today operate their discipline and profession at over two generations’ remove from a time when geopolitics had constrained international law to its basic functions. Shifts in world power now are laying bare the premises of a “rules-based international order,” however, and international law either will adapt or risk decline. If it is to adapt, then international law must acknowledge and respect the geopolitical realities behind its past success.

BIOGRAPHY:  Thomas D. Grant is a Senior Fellow of Wolfson College and a Fellow of the Lauterpacht Centre for International Law at the University of Cambridge and a Visiting Fellow of the National Security Institute at George Mason University. He has held visiting fellowships at the Max Planck Institute for Public International Law at Heidelberg (under an Alexander von Humboldt Foundation German Federal Chancellor Scholarship), the U.S. Institute of Peace (as a Jennings Randolph Senior Fellow), and the Hoover Institution at Stanford (as Edward Teller Fellow). From 2000-2002, Dr. Grant was Anna Biegun Warburg Junior Research Fellow at St. Anne’s College, Oxford. 

As a practicing lawyer, he has served, inter alia, on teams acting on behalf of States at the International Court of Justice (ICJ) and before arbitral tribunals under the UN Convention on the Law of the Sea and has advised governments and businesses on international law matters, including treaty negotiations. He is author, co-author, or editor of ten books and contributing editor to the forthcoming 10th edition of Oppenheim’s International Law, the most-cited international law treatise in the English language. 

Dr. Grant’s current projects include exploratory steps toward a Washington, DC-based geopolitics initiative; and a study on the history of China’s relationship to the Nuclear Non-proliferation Treaty (NPT). He served in the Trump Administration as Senior Advisor for Strategic Planning in the Bureau of International Security and Nonproliferation at the Department of State, 2019-2021.


Thomas D. Grant, ‘Europe’s Borderlands and China’s Challenge: Why War in Ukraine Matters,’ The SAIS Review of International Affairs (Mar. 12, 2022), available at

Thomas D. Grant, Aggression Against Ukraine: Territory, Responsibility, and International Law (2015), chapter 4 (esp. pp. 128-131) and chapter 7.  

Thomas D. Grant, ‘Annexation of Crimea,’ (2015) 109(1) American Journal of International Law 68-95.  

Thomas D. Grant, ‘Doctrines (Monroe, Hallstein, Brezhnev, Stimson), Max Planck Encyclopedias of International Law (2014).