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How Napoleonic strategy and tactics influenced generations of American officers.

It is easy to characterize the U.S. Army in the 19th century as an organization of amateurs lacking the professionalism of its European contemporaries. The United States Military Academy at West Point has suffered from a similar characterization—being viewed as just an engineering school that spent little time preparing graduates for higher-level military service. In fact, American institutions and military thought of this period are often criticized as being poor copies of European institutions and ideas. This was partially true, as the U.S. Army did adopt the principles and doctrines of French warfare developed during the Wars of the French Revolution, which included the early Napoleonic Wars, but the French influence on American warfare produced no mere copy. Primarily through the efforts of Dennis Hart Mahan, the longtime professor of engineering and the science of war, and French general and writer Antoine-Henri Jomini, an expert on Napoleonic theory, decades of West Point cadets received an education in military theory directly inspired by French warfare but adapted to the American military tradition. Those graduates carried that American adaptation with them to the regular army and first used it to achieve success on the battlefields of the Mexican-American War.

The United States Military Academy at West Point was founded in 1802 by the Jefferson administration as a way to encourage a more egalitarian officer corps. Prior to the academy’s founding, the officer corps was dominated by elitists who also happened to be Federalists and thus politically opposed to Jefferson. Jefferson hoped that the academy would create a more geographically, economically, and politically diverse officer pool.

Originally, the academy functioned as a trade school for the Corps of Engineers and produced many effective engineering officers for the War of 1812. But the appointment of Sylvanus Thayer as superintendent in 1817 transformed it from a small branch of the Corps of Engineers into an engineering and officer training school of renown. Thayer had attended West Point, entering in 1807, soon after its founding. Because of his previous engineering education, he graduated with the class of 1808. He spent the War of 1812 in Virginia and distinguished himself through the arrangement of the fortifications and defense of Norfolk. In 1815 the War Department sent Thayer to Europe to amass a modern military library and to study the curriculum of the École Polytechnique, which Napoleon had turned into a military school for officers in 1804. Thus, Thayer observed French military education firsthand. This experience led him to appreciate French military thought and the effectiveness of French warfare.

When Thayer became the superintendent of the academy, he immediately undertook to make it more than just a school for engineers. He set out to create an American version of French officer education by adopting both the form and the spirit of French military educational techniques, and he succeeded: He changed West Point’s academic organization, sorting the cadets into sections by ability and tailoring course material to each section. Thayer introduced semiannual written and oral examinations in 1819 and brought daily recitations into the classroom. His new curriculum was based on a solid foundation of mathematics and French language, which cadets used to develop their knowledge of engineering, literature, law, history, and the science of war. Thayer’s 16 years as superintendent transformed the academy into an institution capable of providing cadets with a comprehensive education in military art and science.

The French educational techniques introduced by Thayer were very different from today’s undergraduate experience. The professors did not lecture in the classroom, and there was very little peer-to-peer learning. Instead, the recitation system required students to read and master material prior to coming to class. Class time was for students to demonstrate mastery of the course material, often by solving problems on the blackboard and briefing the professor and the class on those solutions. In the 19th century the responsibility for undergraduate education rested with the student not the instructor, and throughout society learned people most often turned to books for knowledge. This was true of the citizen-soldiers of the American Revolution as well as of the West Point cadets under Thayer’s leadership. So any serious study of the intellectual development of the U.S. Army in the 19th century must include an understanding of the required texts and military regulations of the West Point curriculum.

As an engineer, Thayer considered the engineering program at West Point to be the principal way for cadets to learn military art and science. He appointed Claudius Crozet as the first professor of engineering at West Point. Crozet was a veteran of the Napoleonic Wars and brought the French study of military engineering and the science of war to the academy. His engineering course mirrored those taught at the Military School of Engineers and Artillerists in Metz. The War Department supported Crozet’s approach by commissioning an English translation of Simon Gay de Vernon’s A Treatise on the Science of War and Fortification, and it became the central text of the academy’s engineering program.

Gay de Vernon had earned an excellent reputation as an engineer during the Wars of the French Revolution and became the first professor of engineering and fortification at the École Polytechnique. He wrote Treatise expressly for the students of the École, and in 1805 Napoleon personally endorsed Treatise for use in officer education. Crozet adopted the book because it had been used to train thousands of French officers for the Napoleonic Wars. Like Thayer, Crozet believed that the advances in military art developed through the Wars of the French Revolution represented the epitome of modern warfare and that there was no better way to educate American officers in French warfare than through the Gay de Vernon text.

Captain John O’Connor translated the West Point edition of Treatise and added an appendix containing the most current military theory available in any language. Treatise began with a discussion of the role engineering played in officer education. For Gay de Vernon, line infantry and cavalry officers required an understanding of mathematics, geometry, and field fortifications to be successful on the battlefield. Artillery officers required those subjects plus knowledge of science, physics, and engineering. However, generals had to master all that knowledge plus an intuitive sense of coup d’oeil—the ability to quickly assess battlefield situations and respond accordingly. Thus the study of engineering became the heart of the study of war.

The first of the three sections of the history of the science of war, covering formations, techniques, and the evolution of the military arts from the ancients through the military revolution to Treatise was a the French Revolution. While providing a general history of European warfare, Vernon posited a dichotomy between the armies of Frederick the Great and the armies of the French Revolution. He stated that French armies were victorious on the battlefield because they were primarily infantry armies composed of units able to perform both light and heavy infantry tasks. Several chapters detailed the formations, organization, and orders of battle that the warfare of the French Revolution required. The greatest weapon of the victorious infantry was the bayonet. All other arms were auxiliary and existed only to support the infantry attack. The primary objective of artillery was to disrupt enemy infantry and only thereafter to focus on enemy artillery and obstacles. Skirmishers advanced in front of the main infantry line, then joined the main infantry charge. Vernon used historical examples to demonstrate these principles as part of his treatment of grand tactics. He worked from the battlefield to the campaign and emphasized that decisive action was always offensive in nature; the defensive was only assumed as a means to return as quickly as possible to the offensive.

The second and third parts of the Treatise concerned field and permanent fortifications and had a traditional engineering approach with more mathematics and geography than tactics or strategy. Vernon described at length how offensive operations were supported through fortification and how those fortifications could be successfully attacked.

The appendix, titled “A Summary of the Principles and Maxims of Grand Tactics and Operations,” encapsulated the thinking of the most celebrated military minds of Europe, especially Antoine-Henri Jomini, “whose work,” O’Connor said in the introduction to the Treatise, “is considered a masterpiece, and as the highest authority.” The appendix began with the maxim that all strategy came down to the ability to carry your strength against the enemy’s decisive point. Then O’Connor used Jomini’s central idea of offensive war: On the offensive, successful generals used infantry armies supported by artillery and cavalry to move against the enemy’s weak points. The appendix served to reinforce the lessons of the main text, and after working through the entire Treatise, cadets had heard from the greatest theoretical minds of Europe and had learned the essential elements of French warfare.

With its new focus on academic excellence and modern engineering, West Point rapidly be- came the premier engineering institution in America. By 1822 Thayer’s acquisitions had made the West Point library one of the best in the country. Although 50 percent of the holdings were physical sciences and engineering texts, 40 percent were devoted to the science and history of war—indicative of the importance Thayer placed on the study of warfare. Not surprisingly, the majority of the books were in French, by French authors, or about the Wars of the French Revolution and the Napoleonic period. This reinforced the centrality of French warfare for generations of West Point cadets, a belief affirmed by these lines from the North American Review in 1832:

One reason for introducing French into the course of studies, independently of the consideration, that every well-educated young man ought to be acquainted with that language, is to enable the cadets to read French works with facility, many of their textbooks being the productions of French authors. It is, we believe, the universal opinion of scientific men, that French writers have been much more successful and happy in their investigations and explanations of the sciences generally, and of that of war in particular, than those of any other nation. It is both an evidence and an effect of this opinion, that a large portion of the works on scientific and military subjects, contained in the library at West Point, are the productions of French authors; and the cadets derive great benefit from this collection.

Throughout the 1820s these French writings, educational techniques, and ideas played a central role in the West Point curriculum. Thayer also sought to replace the academy faculty that he had inherited with academy graduates in an effort to institutionalize his legacy. In 1830 he put a recent graduate in charge of the engineering program. Thus, Crozet’s program remained in place, essentially unchanged, and was responsible for the intellectual development of some of the most important graduates to participate in both the Mexican-American War and the Civil War, among them Albert Sidney Johnston, Samuel Heintzelman, Silas Casey, Joseph E. Johnston, and Robert E. Lee.

In 1830 Thayer appointed Dennis Hart Mahan, a West Point graduate of the class of 1824, as professor of military and civil engineering. He had studied engineering at the French school in Metz from 1826 to 1830 and returned to West Point convinced that the engineering course and the Vernon text needed to be updated—though hundreds of copies of the Treatise remained part of the reference set of each cadet through 1844. Mahan created a unique synthesis that blended the French doctrines of the Wars of the French Revolution—through the language of Antoine Jomini and the battles of Napoleon—with the realities of warfare in North America. His approach and 40 years at West Point had a profound impact on generations of graduates, and his writings influenced many of the officers in the Mexican-American and Civil Wars.

Mahan changed the engineering course with new material, including a series of supplemental notes focused on purely military topics. With sections titled “Composition of Armies” and “Strategy,” these notes provided cadets with the same fundamentals of French warfare as in the Treatise but in a more accessible format. In “Strategy,” Mahan stated his fundamental principle, that “the object of every war ought to be to gain an advantageous peace, and this object can be attained alone by decisive strokes.” This view mirrored Jomini’s and made offensive operations the key to victory.

Mahan’s “Strategy” also contained a “Battle” section that outlined how the different arms worked together to defeat an enemy. Again, it emphasized the primacy of the offensive, with artillery fire to precede light troops in advance of the main infantry formation attacking the enemy’s decisive point—often with the bayonet. He also stressed the importance of position. Given the great distances and varying terrain of North America, Mahan counseled commanders to match their orders of battle to the terrain and geography of the battlefield. His notes thus provided cadets with a concise American version of the fundamental principles of French warfare.

In addition to his supplemental notes, in 1836 Mahan produced the first of a series of military monographs. A Treatise on Field Fortification presented the principles and techniques of fortification and emphasized its importance to militia and irregular troops. Fortifications became an essential element of American defensive warfare, since they allowed untrained militia troops to fight more disciplined regular soldiers on an equal footing. He produced a remarkably straightforward text for the design and construction of fortifications that enabled any militia unit to construct them. Clearly a proponent of a disciplined professional army, Mahan also discussed the importance of discipline and training for the militia as a means to their becoming regular soldiers.

For the purposes of cadet instruction the more innovative sections are those concerned with the defense of field fortifications. Mahan proposed that the defensive forces use artillery and rifle fire to slow and disrupt the advancing enemy infantry. Then, as the enemy attack reached the parapets, he advocated that the defending troops sally forth in a bayonet attack to break the enemy. Essentially, he advocated that the defense adopt the organization and principles of the offense. Both actions thus culminate in an infantry bayonet charge. For him, the bayonet attack remained the most fundamental and decisive element of both offensive and defensive operations.

Through Mahan’s notes, book, and classroom recitations, West Point graduates George Meade, Montgomery Meigs, Braxton Bragg, Robert E. Lee, Jubal Early, Joseph Hooker, P. G. T. Beauregard, William Hardee, Henry Halleck, William Tecumseh Sherman, George Thomas, Ulysses S. Grant, and many more who would figure largely in the wars soon to come absorbed the principles of French warfare as the principles of modern warfare.

The lessons of West Point were not treated as mere classroom exercises by the graduates who fought on the battlefields of the Mexican-American War. Many American actions in that conflict are clear examples of the lessons of French-inspired warfare. With the exception of the Battle of Buena Vista, the war’s major engagements consisted of American attacks. From Zachary Taylor’s actions in northern Mexico to Winfield Scott’s campaign for Mexico City, American troops attacked in formations from squads to divisions. Whenever possible, the Americans began their attacks with infantry troops sent out in front as skirmishers, as in Taylor’s initial deployment at Palo Alto. That battle saw the artillery focusing on the enemy infantry with such effect that the battle required no infantry assault. Most of the battles were American attacks against fortifications, and in this respect the West Point graduates remembered Mahan’s lessons well. The assault at Molino del Rey, led in part by Lieutenant Ulysses S. Grant, used darkness to get close to the enemy fortification and engaged the defenses in a single great rush. The assault on Chapultepec began with a two-hour bombardment, followed by a frontal assault led by the skirmishers of Captain Joseph Johnston’s regiment. Several frontal assaults of the Mexican position of the tête de pont (bridgehead) during the Battle of Churubusco caused it to fall to American bayonets.

In these and other actions, the academy lessons, based on the principles of French warfare, guided its graduates to victory on the battlefields of Mexico and would be echoed again when graduates fought one another on the battlefields of the American South.


Michael Bonura, a lieutenant colonel in the United States Army, taught military history at the United States Military Academy at West Point from 2009 to 2010. His first book, Under the Shadow of Napoleon: French Influence on the American Way of Warfare from the War of 1812 to the Outbreak of World War II, was published in 2012.

Originally published in the October 2014 issue of Military History Quarterly. To subscribe, click here.