Toward a Professional Military: A Definitive Guide to Early 19th-Century US Military Professionalism and the War with Mexico

Chronology of Professional Military Development and the Mexican War

• $1821$: Mexico gains independence from Spain.
• $1824$: Artillery School established at Fort Monroe in Virginia.
• $1826$: Infantry School established at Jefferson Barracks in St. Louis.
• $1832$: Posthumous publication of Karl von Clausewitz's On War.
• $1836$: Texas wins independence from Mexico.
• $1838$: Antoine Henri Jomini publishes Summary of the Art of War.
• $1845$: United States annexes Texas as the $28th$ state.
• $1846$:
  • Publication of Henry W. Halleck's Elements of Military Art and Science.
  • Battle of Palo Alto and Battle of Resaca de la Palma.
  • United States declares war on Mexico.
  • Kearny occupies New Mexico.
  • Battle of Monterey.
• $1847$:
  • Publication of Denis Hart Mahan's Out-Post.
  • Battle of Buena Vista.
  • Scott occupies Vera Cruz.
  • Battles of Cerro Gordo, Contreras, Churubusco, and Chapultepec.
  • Scott occupies Mexico City.
• $1848$: Treaty of Guadalupe Hidalgo signed.

The Revolution in Military Affairs and Napoleon Bonaparte

• The Impact of the French Revolution ($1789$): Introduced a revolution in military affairs characterized by intense nationalism. The French Republic mandated armed service for all citizens (conscription), creating massive armies that sought to export republicanism across Europe.
• Total War Resources: Warfare evolved into a year-round endeavor harnessing total national resources. Conscription provided an inexhaustible pool of manpower, leading generals to accept higher casualty rates in pursuit of victory.
• Napoleon Bonaparte’s Strategy: Napoleon transformed the traditional strategy of annihilation into a doctrine of overwhelming battle designed to destroy the enemy's army and extract a psychological toll.
  • Maneuver: Used swift movement to envelop enemy forces.
  • Tactics: Employed mobile artillery to fire case shot at close range.
  • Organization: Tactical placement of divisions provided strategic advantages before engagements began.

Modern Military Thinkers: Jomini and Clausewitz

• Antoine Henri Jomini ($1779-1869$):

  • Background: Served as a major general in Napoleon's army and later for Alexander I of Russia. Focused on logistics and troop movements.
  • Philosophical Approach: Influenced by Enlightenment thought; sought to minimize the human and financial costs of battle while applying Napoleon's offensive brilliance.
  • Universal Principles: Argued warfare followed scientific, discoverable rules.
  • Four Primary Rules for Battle:
    1. Maneuver forces to strike the enemy's most important points and communications without vulnerability.
    2. Concentrate forces against only a portion of the enemy's strength.
    3. Determine the decisive point of the battlefield and maneuver mass against it.
    4. Ensure mass is concentrated swiftly and in a well-timed, coordinated manner.
  • Strategic Objectives: Emphasized the strategic initiative—forcing the opponent to react. Preferred gaining territory over total annihilation of the enemy.

• Karl von Clausewitz ($1780-1831$):

  • Background: Served in Prussian and Russian armies; superintendent of the Prussian Kriegsakademie.
  • On War: Viewed war as a violent act to make an opponent fulfill one's will, serving as a means of diplomacy.
  • Key Concept - Friction: War is human activity filled with unplanned variables and surprises. Only military genius/flexibility can minimize friction.
  • Key Concept - Center of Gravity: Masses should focus on the enemy's center of gravity, which could be the army or public opinion.
  • Destruction of Will: Unlike Jomini, Clausewitz argued victory required destroying the opponent's military force and their will to use it.

Professionalization of the United States Military

• West Point (U.S. Military Academy): Became the center for Napoleonic study.
  • Growth of the Officer Corps: Commissions of West Point grads rose from $14.8\,percent$ in $1817$ to $63.8\,percent$ in $1830$ and $75.8\,percent$ by $1860$.
  • Sylvanus Thayer: Superintendent who integrated European strategic thought into the curriculum, though restricted by lack of funds and the school's focus on engineering.
• Denis Hart Mahan: Protégé of Thayer and professor of military science. Taught warfare as both science and art (strategy, fortifications, logistics).
  • Published Work: Out-Post ($1847$) emphasized maneuver and deception to gain position at the least cost.
• Henry W. Halleck: Student of Mahan who wrote Elements of Military Art and Science ($1846$).
  • Applied Jominian thought to the U.S., focusing on defensive policy and fixed coastal fortifications to protect major cities and resources.
• European Observation Missions:
  • Lieutenant Daniel Tyler: Translated French artillery plans and secret weapon designs ($1828-1829$).
  • $1840$ Ordinance Tour: Officers toured munitions factories across Europe.
  • The Crimean War ($1855-1856$): Secretary of War Jefferson Davis sent Major Richard Delafield, Major Alfred Mordecai, and Captain George B. McClellan to study field logistics, arms design, and hospital organization.

Standardization and Specialized Education

• Schools of Practice:
  • Artillery School of Practice ($1824$): Fort Monroe, Virginia.
  • Infantry School of Practice ($1826$): Jefferson Barracks, St. Louis.
  • Cavalry School of Practice: Established at Carlisle Barracks, Pennsylvania ($1855$).
• Board of Ordinance: Tested and approved new technologies (percussion rifles, breech-loading weapons), acting as the Army's first research and development program.
• Naval Professionalization: Lagged behind the Army; relied on an apprentice system.
  • George Bancroft: Established the U.S. Naval Academy at Annapolis in $1845$.
  • Naval Issues: The Somers mutiny investigation ($1842$) and inconsistent discipline highlighted the need for reform.

The Mexican-American War: Causes and Initial Conflicts

• Political Context: President James K. Polk sought California and a border settlement. Texas annexation in $1845$ led Mexico to break diplomatic ties.
• Outbreak of Hostilities: Polk ordered Zachary Taylor to the Rio Grande (Fort Texas).
  • April 23, 1846: Mexican troops ambushed a patrol of $60$ dragoons; $11$ were killed.
  • Declaration of War: May 11, 1846. Congress authorized $10 \times 10^6\,dollars$ and $50,000$ volunteers.
• Early Battles: Taylor won at Palo Alto (May 8) and Resaca de la Palma (May 9).

Military Campaigns and Major Engagements

• The Three-Pronged Strategy:

  1. Taylor: Drive west from Matamoras to Monterey, then south.
  2. Wool: Move south from San Antonio toward Saltillo.
  3. Kearny: Move from Fort Leavenworth to Santa Fe and San Diego.

• Northern Campaigns:

  • Monterey (September 1846): Taylor's force of over $3,000$ regulars and $3,000$ volunteers engaged $7,000$ Mexican troops in house-to-house fighting.
  • Buena Vista (February 1847): Taylor’s $5,000$ men faced Santa Anna’s $20,000$. Jefferson Davis’s Mississippi Dragoons and effective artillery use turned the tide. Taylor lost $264$ men; Santa Anna lost nearly $2,000$.
  • New Mexico and California: Kearny occupied Santa Fe (August 1846) and instituted the "Kearny Code." Later combined forces with Stockton and Fremont to take Los Angeles (January 10, 1847).

• Winfield Scott's Central Mexico Campaign:

  • Vera Cruz (March 1847): First major amphibious landing in U.S. history with $10,000$ troops. City surrendered after bombardment by ten-inch mortars and naval guns.
  • Cerro Gordo (April 18, 1847): Captain Robert E. Lee found a route around Mexican cliffs; Scott’s artillery forced a chaotic retreat of $3,000$ prisoners.
  • Contreras and Churubusco (August 1847): Robert E. Lee found a path through the "Pedregal" lava field. Americans suffered $1,000$ casualties; Mexicans lost $4,000$.
  • The San Patricios: A unit of over $200$ American deserters (mostly Irish Catholics) captured at Churubusco; $35$ were executed.
  • Chapultepec and Mexico City (September 1847): Three-pronged assault on the castle (the Mexican West Point) followed by house-to-house fighting until surrender.

Political Friction: Lincoln and the "Spot" Resolutions

• Discussion: Abraham Lincoln, then a Whig Representative from Illinois, challenged Polk’s war justification through the "spot" resolutions, demanding to know the exact spot where American blood was shed.
• Lincoln’s Correspondence: In a letter to Elihu B. Washburne (April 30, 1848), Lincoln discussed the political ambitions generated by the war, favoring General Zachary Taylor for the Whig presidential nomination over Henry Clay, Scott, or Justice McLean.

Treaty of Guadalupe Hidalgo and War Legacy

• Negotiations: Conducted by Nicholas Trist (who ignored a recall order from Polk) and General Scott.
• Treaty Terms ($1848$):
  • U.S. acquired New Mexico, Arizona, Nevada, Utah, California, and portions of Wyoming and Colorado.
  • Rio Grande established as the Texas boundary.
  • U.S. paid Mexico $15 \times 10^6\,dollars$ and assumed claims against Mexico.
• Human and Financial Cost:
  • $13,780$ American dead (only $1$ in $8$ died in combat; most died from disease).
  • Over $5,000$ total desertions (regulars and volunteers).
  • Total cost: approximately $100 \times 10^6\,dollars$.
• Long-term Consequences: The war exacerbated the sectional crisis over slavery in new territories, setting the stage for the Civil War. It also cemented the professional identity and careerism of the officer corps.