“The National Security Constitution in the Twenty-First Century is quite simply the best book ever written about its daunting subject. It is as brimming with practical advice as it is steeped in theoretical sophistication. Harold Hongju Koh’s topic is nothing less than the intricate system through which the United States Constitution structures America’s institutional arrangements for coping with global complexity and managing the challenges of securing the Nation while respecting self-government, adhering to the rule of law, and respecting the rights of all those affected by an ever more powerful federal Executive Branch. Written with the perspective that only experience can nurture, the wisdom that no amount of experience can ensure, and the brilliance that alone can bring wisdom and experience into alignment, Koh’s masterpiece will be required reading long after the dust has settled on the many crises that grip our attention as the first third of the twenty-first century comes to an end. But trying to cope with those crises without first reading this magisterial work would be sheer folly.”—Laurence Tribe, Harvard University“Harold Hongju Koh represents that extraordinary public intellectual capable of dexterously operating at the highest levels of academia, government, and multilateral fora with equal skill and insight. In The National Security Constitution in the Twenty-First Century, he shares a timely analysis and provocative blueprint for fixing broken institutions which the free world desperately needs restored to their proper equilibrium. The world looks to the United States to be who we say we are, and Americans who believe in that hard-earned exceptional role in the world look to Harold to help our institutions find our way back to that essential place. We would all do well not just to read his work but to act on it.”—John Kerry, 68th Secretary of State, President Biden’s Special Presidential Envoy for Climate“Few people understand the complex workings of our National Security Constitution better than Harold Hongju Koh, and no one analyzes and explains them better. In this outstanding scholarly achievement, Professor Koh describes the growing dysfunction caused by institutional failures in all three branches of our federal government, and recommends a badly needed, workable strategy for constitutional repair.”—Chris Coons, U.S. senator from Delaware“This book will be the new bible for security and international law, not just in the USA but all over the world. It represents a life’s work that will inspire scholars, judges, and public servants for generations.”—Justice Rosalie Silberman Abella, Supreme Court of Canada (retired), Samuel Pisar Visiting Professor, Harvard Law School“Harold Hongju Koh is a giant among those who think and live the American Constitution’s approach to foreign policy and international relations. The National Security Constitution in the Twenty-First Century, his latest contribution to the field, is a tour de force. It is must reading for anyone interested in the subject.”—John Sexton, president emeritus, New York University