I HAVE ACCRUED a tremendous number of debts in the process of researching and writing this book. Any scholar hoping to say something new about Henry Clay, James K. Polk, Abraham Lincoln, or the war between the United States and Mexico is forced to contend with a daunting historiography on each of these topics. This book was only possible because generations of remarkable scholars sorted through letters, edited papers, and gracefully synthesized existing scholarship to make sense of these men and the war that drew them together. My reliance on the work of Jean H. Baker, K. Jack Bauer, Albert Jeremiah Beveridge, Gabor Boritt, Eric Foner, William E. Gienapp, David and Jeanne Heidler, Daniel Walker Howe, Frederick Merk, Mark E. Neely Jr., Merrill Peterson, Robert Remini, Joel Silbey, and particularly Charles Sellers will be obvious to readers familiar with their classic works.
My debt to the institutions and individuals who facilitated my research is no less acute, and easier to narrate. The John Simon Guggenheim Foundation, American Philosophical Society, Gilder Lehrman Foundation, Huntington Library, and, at Penn State, the Institute for the Arts and Humanities and Richards Civil War Era Center each provided financial support for this project. Librarians and archivists at the Abraham Lincoln Presidential Library, Amon Carter Museum of American Art, Ashland: The Henry Clay Estate, Bancroft Library, British Library, Chicago History Museum, Daughters of the American Revolution Library, Historical Society of Pennsylvania, Huntington Library, James K. Polk Memorial Association, Library of Congress, Louisiana State University Special Collections, Massachusetts Historical Society, Monticello, New-York Historical Society, Ohio Historical Society, Santa Barbara Mission Archives, and Wisconsin Historical Society were enormously helpful, as was the staff of the Penn State University libraries, particularly Eric Novotny. Agnes Hamberger at the Saratoga Springs History Museum deserves special thanks not only for her extensive assistance with research but also for her unflagging support of this project. Former Jacksonville, Illinois, mayor Ron Tendick generously shared his research on the Hardin family. Anne Brinton slogged through microfilm on my behalf, Alexandria Lockett and William Cossen helped with copyediting and proofreading, and Peter Van Lidth de Jeude provided translations of German accounts of the war.
I am also in the debt of colleagues who generously provided their time and knowledge to making this study better. Kevin Adams, John Belohlavek, Andrew Burstein, Andrew Cayton, Brian DeLay, Richard Doyle, Daniel Walker Howe, Nancy Isenberg, Alexis McCrossen, Mark E. Neely Jr., Carol Reardon, and Andrés Reséndez each read and commented on a draft of this manuscript. Sean Trainor managed to complete a detailed line edit of the initial draft by lamplight while camping. Their suggestions, corrections, criticism, and support have vastly improved this book and saved me the embarrassment of a great number of errors. Remaining errors are of course my own.
My wonderful colleagues and students at Penn State University have helped me refine my arguments, as have audiences at lectures and conferences over the previous eight years. Discussions about this project with William Blair, Gregg Cantrell, Patricia Cline Cohen, Robert Devens, Jonathan Earle, Gary Gallagher, Kristin Hoganson, Walter Johnson, Anthony E. Kaye, Robert E. May, Chandra Manning, Francesca Morgan, Anne C. Rose, Naoko Shibusawa, Michael Vorenberg, Ronald and Mary Zboray, and Andrew Zimmerman have been particularly useful. Mark Neely’s knowledge of all things Lincoln has been a much-appreciated resource from the earliest stage of this project. The Society for Historians of the Early American Republic has proven a wonderfully nurturing environment for thinking through the history of this most crucial era.
My brothers, Mike and Ken Greenberg, have shaped my approach to the war over years of discussions about U.S.-Mexico relations. My parents, Kenneth and Jane Lee Greenberg, have long nurtured my interest in history. They always hoped I would write a book that people might actually read. Jessica Greenberg has been a tireless booster of my work. Daily e-mails with Alexis McCrossen have proven a crucial source of analysis, inspiration, and support. Rich Doyle, always eager to toss ideas back and forth, kept me focused on the big picture. It is an honor to publish this book with Knopf. My editor, Andrew Miller, and editorial assistants Andrew Carlson and Mark Chiusano have been a pleasure to work with. Without the encouragement of my indomitable book agents, Sydelle Kramer and Susan Rabiner, this book would never have been written. They know how much they have shaped this project.
Finally, my greatest thanks go to my family, Rich, Jackson, and Violet Doyle. Without their love and support I would be nowhere. They have put up with my obsessive discussion of the Hardin family, out-of-town research trips, and general book-related distraction for too many years. I offer them the dedication of this book knowing full well the gesture is nothing compared to the debt I owe each of them.