This project is both a wartime biography and an examination of the American effort in France during the First World War. At its core, the narrative follows the military career of Major General James G. Harbord. His time in France saw Harbord serve in the three main areas of the American Expeditionary Forces: administration, combat, and logistics. As chief of staff to AEF commander General John J. Pershing, Harbord was at the center of the formation of the AEF and the development of its administrative policies. He organized and managed the AEF General Staff and served as Pershing's most trusted subordinate. In May of 1918, Harbord transferred to the fighting line, taking over command of the 4th "Marine" Brigade. During his time with the 4th Brigade, and later as commander of the 2nd Division, Harbord played a significant part in the battles of Belleau Wood and Soissons. A dedicated supporter of Pershing's tactics of "open" warfare, Harbord's failings as a combat commander showed the limits of American tactical experience. For the final four months of the war, Harbord took over control of the AEF's logistical system, the Services of Supply. Though he proved an able administrator, the American supply system approached total collapse in the fall of 1918, and was prevented only by the signing of the Armistice. In all three of these roles, Harbord embodied the emergence of the military manager in the American army. The First World War illustrates that war had grown so large and complex that it required officers whose primary talents lay not in leading men in combat, but in the areas of administration and management of large bureaucratic organizations. James Harbord was one of the first, and best, examples of this new type of officer.

This project is both a wartime biography and an examination of the American effort in France during the First World War. At its core, the narrative follows the military career of Major General James G. Harbord. His time in France saw Harbord serve in the three main areas of the American Expeditionary Forces: administration, combat, and logistics. As chief of staff to AEF commander General John J. Pershing, Harbord was at the center of the formation of the AEF and the development of its administrative policies. He organized and managed the AEF General Staff and served as Pershing's most trusted subordinate. In May of 1918, Harbord transferred to the fighting line, taking over command of the 4th "Marine" Brigade. During his time with the 4th Brigade, and later as commander of the 2nd Division, Harbord played a significant part in the battles of Belleau Wood and Soissons. A dedicated supporter of Pershing's tactics of "open" warfare, Harbord's failings as a combat commander showed the limits of American tactical experience. For the final four months of the war, Harbord took over control of the AEF's logistical system, the Services of Supply. Though he proved an able administrator, the American supply system approached total collapse in the fall of 1918, and was prevented only by the signing of the Armistice. In all three of these roles, Harbord embodied the emergence of the military manager in the American army. The First World War illustrates that war had grown so large and complex that it required officers whose primary talents lay not in leading men in combat, but in the areas of administration and management of large bureaucratic organizations. James Harbord was one of the first, and best, examples of this new type of officer.

Many scholars of the First World War have examined the European armies in new ways that have shown not only how those armies actually fought along the Western Front, but how they changed their ideas and methods over time, and why they fought the way they did. This dissertation does the same for the American Expeditionary Forces (AEF). It examines how four AEF divisions (the 1st, 2nd, 26th, and 77th) planned and conducted their battles, what they learned about modern combat in those battles, and how they adapted their doctrine, tactics, and other operational methods during the war. Although this dissertation describes AEF training and operations, its focus is on ideas and methods, and the changes in both during the war. It shows that when the United States joined the war in 1917, the U.S. Army was doctrinally unprepared for the industrial combat of the Western Front. It demonstrates that General John J. Pershing and other AEF leaders accepted this inadequate prewar doctrine, with only minor modification, as the official doctrine of the AEF. Many early American attacks suffered from these unrealistic ideas, which retained too much faith in the infantry rifleman on a battlefield dominated by artillery, machine guns, and barbed wire. However, this dissertation also shows that AEF divisions adjusted their doctrine, tactics, and other operational methods, as they fought. Experienced divisions prepared more comprehensive attack plans, employed more flexible infantry formations, and maximized firepower to seize limited objectives. Although some of these adaptations were accepted by senior officers at AEF General Headquarters (GHQ), the American First Army, and the various corps, the lessons seem to have been learned first, and best, by officers and men within the combat divisions. Often the extent of these changes reduced the operational relevance of senior officers at GHQ, including Pershing, many of whom failed to make the same doctrinal adjustments. In short, this study exposes the battle of ideas waged within the AEF, between those who adhered to the traditional, human-centered ideas of the prewar army and those who increasingly appreciated the modern, industrial ideas then prevalent in the European armies.

Many scholars of the First World War have examined the European armies in new ways that have shown not only how those armies actually fought along the Western Front, but how they changed their ideas and methods over time, and why they fought the way they did. This dissertation does the same for the American Expeditionary Forces (AEF). It examines how four AEF divisions (the 1st, 2nd, 26th, and 77th) planned and conducted their battles, what they learned about modern combat in those battles, and how they adapted their doctrine, tactics, and other operational methods during the war. Although this dissertation describes AEF training and operations, its focus is on ideas and methods, and the changes in both during the war. It shows that when the United States joined the war in 1917, the U.S. Army was doctrinally unprepared for the industrial combat of the Western Front. It demonstrates that General John J. Pershing and other AEF leaders accepted this inadequate prewar doctrine, with only minor modification, as the official doctrine of the AEF. Many early American attacks suffered from these unrealistic ideas, which retained too much faith in the infantry rifleman on a battlefield dominated by artillery, machine guns, and barbed wire. However, this dissertation also shows that AEF divisions adjusted their doctrine, tactics, and other operational methods, as they fought. Experienced divisions prepared more comprehensive attack plans, employed more flexible infantry formations, and maximized firepower to seize limited objectives. Although some of these adaptations were accepted by senior officers at AEF General Headquarters (GHQ), the American First Army, and the various corps, the lessons seem to have been learned first, and best, by officers and men within the combat divisions. Often the extent of these changes reduced the operational relevance of senior officers at GHQ, including Pershing, many of whom failed to make the same doctrinal adjustments. In short, this study exposes the battle of ideas waged within the AEF, between those who adhered to the traditional, human-centered ideas of the prewar army and those who increasingly appreciated the modern, industrial ideas then prevalent in the European armies.

Doctor of Philosophy / Department of History / Michael A. Ramsay / This dissertation examines combat leadership in the American Expeditionary Forces (AEF) in infantry and machine gun units at the company level and below to highlight the linkages between the training and professional development of junior officers and noncommissioned officers (NCOs) and the army's overall military effectiveness in World War I. Between 1865 and 1918, the growing lethality of the battlefield had forced changes to tactics and formations that placed novel demands on small unit leaders. The proliferation of new weapons in infantry companies and the thinning and extension of formations required junior officers and NCOs able to exercise an unparalleled degree of initiative and independence while also mastering new tactical and technical skills. When the United States entered World War I, the Regular Army was still grappling with how to reconcile its traditional expectations of small unit leadership with the new "skill sets" required of junior leaders in modern warfare. Faced with the need to produce officers and NCOs to lead its rapidly expanding mass army, the regulars improvised a system for identifying, training, and assigning company-level leaders. Unfortunately, the Regular Army's unpreparedness to wage a modern war, and the host of systemic problems associated with raising a mass army, meant that much of the training of these key leaders was so ill-focused and incomplete that the new officers and NCOs were woefully unprepared to face the tactical challenges that awaited them in France. These problems were only compounded when unexpected casualties among officers and NCOs in the summer and fall of 1918 led to a further curtailment in leader training the U. S. Army. The end result of the U. S. Army's failure to adequately train and develop its junior leaders was that its combat units often lacked the flexibility and "know how" to fight without suffering prohibitively high casualties. When the junior leaders failed, faltered and bungled, the AEF's battles became confused and uncoordinated slugging matches that confounded the plans and expectations of the army's senior leaders. The heavy casualties that resulted from these slugging matches further undermined the AEF's effectiveness by reducing the morale and cohesion of the army's combat units and hindering the army's overall ability to learn from its mistakes due to the high turn-over of junior officers and NCOs.

American participation in the First World War developed slowly throughout 1917 to a mighty torrent during the last six months of the war. United States participation undoubtedly helped not only repel but to stop all German assaults on the Western Front: it had substantially aided in defeating Imperial Germany. Through primary and secondary sources a timeline, as well as a few of the more significant events, has been established following the United States' involvement in the war. Special attention has been focused on the United States Third Infantry Division and its part in the July 15- 17, 1918 Second Battle of the Marne. The Third Infantry Division would see the war throughout its remaining battles and aid in the occupation of Germany. However, it is most famous for the Marne battle.