warfare. The laws of war need not fuss over the line between targetable military and immune civilian assets when UAVs can deliver precision-guided munitions on particular targets.
Reluctance to use force has led western nations to rely on economic sanctions, which punish entire populations. Drones and cyber attacks could provide a more effective alternative by inflicting harm on the target state’s economy, but in a more precise manner. Such an approach may avoid the unintended effects of sanctions and operate much more quickly and reliably, and leave adversaries less time to adapt. To make the most of those new capacities, we should rethink current legal formulas purporting to regulate when military force is lawful against what targets it is used.
New weapons technologies could help the United States and its allies protect international stability. WMD proliferation, international terrorism, human rights catastrophes, and rising regional powers are threatening the liberal post-WWII international order constructed by the U.S. and its allies. Nations will be discouraged from confronting these problems with conventional force. But if new technology reduces the costs of war, while improving its effectiveness, nations may turn to force more often to promote desirable ends. International stability remains a global public good, in that peace benefits all nations regardless of who pays for it. This gives nations a strong incentive to free-ride off the efforts of others to maintain international peace and security. If using force becomes less expensive and more effective, nations may turn to force more readily when the times require it. New weapons may be particularly helpful in situations where a large-scale military response might be excessive, but mere words are insufficient.
New weapons technologies may produce the welcome benefit of limiting the destructiveness of conflict. While the United States, among others, is rapidly developing new means of fighting, these innovations may limit war. Robotics can reduce harm to combatants and civilians by making attacks more precise and deadly. Cyber can more effectively target enemy military and civilian resources without risking direct injury to human beings or the destruction of physical structures. Space satellites will provide the sensors and communications that make possible the rapid, real-time marriage of intelligence and force, and future orbital weapons may create a viable defense to nuclear missiles.
This book proceeds in three main parts. The first two chapters provide a historical overview of war, weapons, and the rules of warfare. We argue in chapters 1 and 2 that expectations about war and force, which may have prevailed some decades ago, do not fit the challenges of our time. Over the course of history, nations have adapted varied notions about the appropriate use of force as wider changes in technology and social organization generated new challenges and opportunities. Chapters 3 and 4 show that the law of war, in particular, has changed over time and the most recent efforts to codify restraints on armed conflict are ill-suited to our present challenges.
Chapters 5, 6, and 7 apply these insights to the new technologies of robotics, cyber, and space. They argue that new technologies give nations the ability to use force more precisely, and thus to exert force with lower harm. Greater precision will allow nations to settle their own disputes with less resort to full-scale hostilities. They will also give nations greater freedom to combat the current challenges to international peace and stability, such as WMD proliferation, regional aggression, and human rights catastrophes.
We have accumulated many debts in the writing of this book. First, we are grateful for comments on portions of this manuscript from Jianlin Chen, Dan Farber, Andrew Guzman, William Hubbard, Richard Johnson, Laurent Mayali, Eric Posner, and Ivana Stradner. Our work also benefitted from workshops at the University of Chicago Law School and the University of California at Berkeley Law School, and presentations at the American Enterprise Institute, the National War College, and the International Symposium on Security and Military Law. Our work was much improved thanks to the assistance of law students Benjamin Bright, Daniel Chen, Sohan Dasgupta, Gabriela Gonzalez-Araiza, Leah Hamlin, Allen Huang, Jonathan Sidhu, Joe Spence, Jon Spiro, and Mark Zambarda.
The authors also wish to thank their literary agent, Lynn Chu, of Writers Representatives, for shepherding this book from its first ideas to the final product. Her keen eye and rigorous thinking helped sharpen and focus this book. We also appreciate the editing of Katherine Wong and are grateful for the support of Roger Kimball, the publisher of Encounter Books.
The authors thank their respective deans for support: Henry Butler at GMU’s Scalia Law School and Berkeley Law School Dean Christopher Edley (and interim deans Gillian Lester and Melissa Murray). Thanks are also due to our colleagues at the American Enterprise Institute, particularly Arthur Brooks, David Gerson, Danielle Pletka, and Gary Schmitt, as well as to James Piereson, president of the Thomas W. Smith Foundation.
Jeremy Rabkin thanks Ariel Rabkin for ongoing technical advice about cyber capacities, Nathaniel Rabkin for insights on contemporary conflicts in the Middle East, and Rhoda Rabkin for keeping all of us grounded.
John Yoo gives thanks to his wife, Elsa Arnett; he feels as lucky today as he has every day for the last three decades to enjoy her love and support. He also thanks his mother, Dr. Sook Hee Yoo, and his brother Chris Yoo. Our family came to the United States because of the wars of its past; this book is an effort to help us understand war better in the future.
Economists call it “creative destruction.”1 Robots are replacing factory workers. Online news sites are displacing newspapers. Passengers are abandoning taxis and summoning part-time drivers with cell phones. Household appliances and security systems are operating on home networks.
New technologies are having an impact beyond the workplace and household. Presidents George W. Bush, Barack Obama, and Donald J. Trump, for example, have ordered robots to kill individuals with precision-guided missiles from the sky. Unmanned aerial vehicles (UAVs) are leading the way for even greater technological innovations in war. The same high-speed computer systems can accelerate financial markets or disrupt national economies. Robotics and precision mapping can automate transportation, even passenger cars. They can also control pilotless aircraft that strike specific buildings or individuals. The same technologies that can assemble and deliver a book, a piece of furniture, or a sophisticated appliance to a customer within days are also enhancing military “productivity,” which means fewer soldiers can kill or incapacitate more of the enemy at lower cost.
Technologies often transcend their original purpose. The cell phone initially freed people to make voice calls without the physical tether of telephone wires. Engineers next added cameras and data communications to the handheld phone. Users could now record and send pictures of controversial police actions, repressive crowd-control measures, or riots. Phones can now distribute these pictures to millions of strangers, before a journalist on the scene could write an eyewitness account. Users can also receive, as well as transmit, a stream of text, data, and information that is rearranging social relationships, consumer activity, travel, and entertainment. A world that is wired allows a vastly wider and more consequential range of communication than telephone calls.
So it is with war. Instead of ending armed conflict, technological advances have expanded it. World War II came to an abrupt end shortly after the United States dropped two atomic bombs on Japan. Many concluded that science had created a weapon so devastating, rational statecraft could never use war as a tool again. “Military alliances, balances of power, Leagues of Nations, all in turn failed, leaving the only path to be by way of the crucible of war. The utter destructiveness of war now blocks out this alternative,” said even General Douglas MacArthur, no pacifist he, on the deck of the USS Missouri during the Japanese surrender. “We have had our last chance. If we will not devise some greater and more equitable system, Armageddon will be at our door.”2 Surely the United Nations would ensure that nations never again looked to settle their differences by resorting to war. It was not to be. Responding to those who hoped that the end of monarchy spelled the end of tyranny, Edmund Burke warned: