I began thinking about these ideas more than a decade ago. At the time, I was preparing for a presentation at an academic conference on executive power at Duke Law School. My focus then was on a legal question: What limits does the Constitution let Congress place on the president’s power to wage war? In continuing to think about these ideas in the years since—as I have made the switch from law professor to executive branch legal advisor to judge—my focus has shifted. My aim is no longer to make a legal argument about what wartime presidents are allowed to do when Congress tries to check them. My aim is to tell the story of what they actually have done.
Along the way, I have received help from too many people to name: students, academic colleagues, librarians, lawyers with whom I have had the privilege to work, friends, and family. I also have had the benefit of the vast body of scholarship—both historical and legal—that addresses this subject.
My first agent, Scott Moyers, encouraged me to write this as a story rather than an argument. He then helped me find a publisher before I left my teaching post at Harvard to join the Obama Administration in January 2009. My second agent, the incomparable Andrew Wylie, helped me revive the project when I came back to Harvard in 2010. The final version of this book exists due to the guidance, patience, and encouragement of my wonderful editor, Alice Mayhew. Thanks are due as well to her excellent assistant, Stuart Roberts.
I benefited over the course of many years from the research assistance of a fleet of incredibly talented and thoughtful students at Harvard Law School: Adam Lebovitz, Joshua Matz, Lauren Moxley, Jacob Reisberg, Andrew Rubenstein, Shivan Sarin, Kyle Wrshba, and David Zimmer. Adam went above and beyond by reading the whole manuscript and by offering excellent suggestions. I have had great and generous help as well from Nancy Katz and George Tauoltsides of the Harvard Law School Library, and from my faculty assistants, Mindy Eakin and Patricia Fazzone.
I have been talking about the limits of the president’s power with my (now former) faculty colleagues at Harvard ever since I first arrived there as an assistant professor in the summer of 1999. I want to give special thanks to Dan Meltzer, who passed away too soon, but who taught me, as he taught all who knew him, how to provide advice; Elena Kagan, who, as my dean, (among her many other kindnesses over so many years), provided the research support that enabled me to write so much of this; John Manning, who invited me to present a version of this book at the public law workshop that he runs with my other former dean, Martha Minow; Martha herself, who helped me think through the idea for this book during a late night walk in New York City; Larry Tribe, who offered some crucially approving words when what became this book was just a draft law review article looking for a journal to accept it; and Jack Goldsmith, one of the great former heads of the Office of Legal Counsel and a generous reader and critic of this manuscript. Thanks are in order, too, to Jerry Frug, who did so much to bring me to Harvard Law School way back when and with whom I have discussed this book and so much else.
My former colleagues at the Office of Legal Counsel have taught me as much as anyone about the challenges of offering legal advice concerning the president’s legal powers. They have been a source of support and inspiration since I first began practicing law. One of those former colleagues deserves special mention: Marty Lederman. We have been in conversation about law generally, and these ideas in particular, for more hours than either of us—or our families—would care to count. Together, Marty and I wrote two lengthy law review articles about this very topic, served together at OLC in the Clinton and Obama administrations, and, for a time, worked on this book together, before Marty had to step away to pursue his own scholarly work as a law professor at Georgetown. His research and thinking inform every page, and most especially the chapter on World War I (though any errors are mine). I could not be more grateful for his friendship.
Three former colleagues from my time in government—Bob Bauer, Dawn Johnsen, and Chris Schroeder—also deserve special recognition. Each kindly and carefully commented on drafts of the book. I am indebted to them for the time they took to do so.
I also want to thank Mallory Heath. A great friend (along with her husband, Brian) of our family, a nanny to our children, and a master research librarian, Mallory has, with her love of the past and deep attention to detail, helped get the notes, pictures, and the text into fighting shape.
The real instigation for this book is my father, Jerry Barron. He was a professor of constitutional law for more than fifty years until he recently retired. He has been my truest teacher of the subject. When I first mentioned to him that I was working on an article about the president’s power in war, he casually said, “I guess you will need to figure out what every president did.” He was, as usual, right. Together, he and my mother, Myra—as careful a reader and legal thinker as there is—have been steadfast in encouraging me in this project, as in all things. They also were instrumental in supporting me, and my then very young family, when we went to Washington in January 2009 to work on some of these issues for real.
I have been blessed as well to have the support of my indefatigable in-laws, Bob and Milly Kayyem. They moved into our house to take care of the kids for a month in the winter of 2008 so that my wife, Juliette, and I could work on the presidential transition—my first introduction to the real-time pressures of advising a wartime president.
My sister, Jen, and my brother, Jon, have been, for this project—as for everything I have done—not only enthusiastic supporters but also great sources of insight.
For Cecilia, Leo, and Jeremiah—my greatest source of joy—there is no longer any need to ask when I will finish it. I am sorry that it took so long. I wrote it with the idea that it might help, in some small way, to ensure that you inherit a future in which the system of checks and balances that we are so fortunate to live under remains up to the task.
And then there is Juliette. I have now known her longer than I have not, though I felt like I had known her forever when I first met her more than twenty-five years ago. There is no one whose judgment about what makes sense and what does not that I trust more. There is also no one who writes more beautifully. And so, there is no one whom I would rather have had read this manuscript, which, amazingly, she did, again and again, draft chapter after draft chapter. There is not much romance in this book. That makes it hard to draw on its themes to close on a proper note. But if this book does have a single message, it is this: It is better to do things together than alone. Thanks to Juliette, I believe that message with all my heart.