When Americans Marched to Mexico City

September 10, 2020
Attack_of_the_Gun_Boats,_San_Juan_de_Ulloa

One hundred seventy-three years ago, American soldiers captured Mexico City. Quite forgotten in the annals of military history, Gen. Winfield Scott’s campaign begun at Vera Cruz ended the Mexican-American War. Peace terms resulted in the $15 million purchase of territory that in time produced Arizona, California, Nevada, and Utah, as well as portions of what would become Colorado, New Mexico, and Wyoming. Scholars have engaged in a considerable amount of handwringing over the ethics of this acquisition. Orthodoxy among historians holds that the Mexican-American War was cruel, wicked, and unjust.

 

 

Still, the Mexico City campaign and the military context in which it occurred are significant for other reasons: Though it belongs to another age, Scott’s march to Mexico City and his subsequent occupation of the enemy capital nevertheless offers a textbook example of campaigning consistent with Army operational doctrine that evolved later. From his establishment of tenets and principles down to the projection of landpower, Scott staged a historic campaign that still speaks to military professionals in the 21st century who, like their predecessors, need to anticipate risk, chance, and uncertainty — enduring features of warfare “inherent in all military operations.”

Identifying the enemy’s historical center of gravity — Mexico City — was one thing, for Scott was an astute student of history as well as military science. The application of landpower to neutralize the capital, however, and to achieve peace with Mexico (the desired end state of the U.S. Army command and civil leadership) was quite another. At the onset of hostilities with Mexico in 1846, the U.S. War Department lacked reliable information from which it could formulate operational plans. Officials had only basic data about Mexico’s climate, natural resources, and topography. True, a rigorous curriculum of engineering and drawing at the U.S. Military Academy had produced officers capable of drawing good maps by 1847, but neither recent nor reliable renderings of routes to Mexico City existed in the U.S. Army on the eve of the war. These would be produced on the ground, after careful but limited reconnaissance over difficult terrain, and among communities hostile to the American intervention. What is more, Americans knew little about the extent and quality of Mexican roads, a central consideration since ordnance and subsistence would be drawn by wagons and mules. These logistical difficulties were much on the minds of American soldiers well into the 20th century. Army officers at the U.S. Army Command and General Staff School in Fort Leavenworth, Kansas, for instance, performed detailed analyses of geography and topography in their assessments of the military challenge and operational environment in Mexico.

For such a campaign to achieve success, logistics and sustainment would prove paramount. The American soldiers would be venturing far from their intended base of supply at Vera Cruz into enemy territory, and in a hostile environment. Scott put the dilemma well when he submitted his invasion plans to the War Department. He wrote that if the Americans advanced into Mexico with too few men and too little materiel, they would be overwhelmed. Conversely, if they advanced with too many troops, the Americans would overwhelm themselves. In the final analysis, Scott recommended that the invasion should be undertaken by no fewer than 12,000 men. He warned ominously that the failure of any expedition would be “fatal to the credit of the administration and the character” of the nation.

Scott left Washington in November 1846 to assemble the invasion force and complete planning for the landing at Vera Cruz. Transporting Scott’s army to Mexico was a seaborne logistical triumph in 1847. One hundred vessels carried American soldiers, artillery, horses, and supplies to the Brazos de Santiago and Tampico from New Orleans. Then the landing force embarked onto two frigates, the Raritan and the Potomac, as well as other assorted vessels. Scott and Commodore David Conner of the U.S. Navy had conducted a reconnaissance and selected the ideal beachhead for the landings.

D-Day came on March 9, 1847. Approximately 140 surf ships — precursors to the Higgins Boats used for Army and Marine amphibious landings in World War II — carried 12,000 soldiers from naval frigates to the shores of Vera Cruz. Cooperation with the U.S. Navy made the landing a joint operation, and the event marked the first large-scale amphibious landing of American soldiers in history. Scott, perched atop the steamship Massachusetts, sailed to the front of the van amid cheers from the sailors and soldiers of the expeditionary force and directed the landings from the vessel’s quarterdeck. Radiant sunlight deepened the water’s immense blue. In less than 12 hours, American troops held the beaches.

Once on shore, and with their guns and supplies in position, American soldiers lay siege first to the castle of San Juan d’Ulloa, and then to the city of Vera Cruz itself, which capitulated on March 29. An absence of wagons delayed Scott’s advance to Mexico City: As March turned to April, Scott could count only 180 wagons — of the 800 he had requested — that were outfitted and ready for the march. Finally, on April 8, Scott’s army began to move, but not before Scott issued a proclamation to “the good people of Mexico.” Americans, wrote Scott, were “the friends of the peaceful inhabitants” of Mexico, “and the friends of your Holy Religion, its Hierarchy and its Priesthood.” Scott promised cash payments for Mexicans who wished to sell goods or subsistence to the army, but warned that irregular violence against American soldiers would be punished “vigorously.” In so doing, historian Timothy Johnson has written in A Gallant Little Army, Scott extended both the “olive branch and sword” to the people of Mexico. Pacifying the local population would prove essential as the American troops marched inland.

Mother Nature antagonized Scott’s army as it advanced. Unlike the mountainous terrain of north-central Mexico, the Valley of Mexico was more easily traversable by mule and wagon. Still, the hot sun tormented soldier and draft horse alike. Hot sands baked soldiers’ feet. In missives and diaries soldiers described the scorching earth and sun. They marched to escape la vomito.

In spite of these limitations, Scott’s army reached Jalapa (now generally spelled Xalapa), then Puebla — a city of some 80,000 people — before reaching San Augustin, and finally, Mexico City. After victories at El Molino del Rey and Chapultepec, American troops entered the city on Sept. 14. They found the Mexican government in disarray. Negotiations proceeded slowly, not least because there were few officials with whom to negotiate. Communication with Washington authorities was slow.

Contra its perception in popular memory, the campaign was costly. From the beginning, and all along the Vera Cruz-Mexico City corridor, U.S. soldiers were vulnerable to guerrilla attacks from Mexican sharpshooters, as well as other irregulars who would lasso soldiers around the neck and drag them to death — or worse. Johnson has written that murders of American soldiers who walked the streets alone at night were commonplace in Puebla. After Scott’s men moved into the Mexican capital on Sept. 14, they encountered dangerous resistance from irregular fighters. Johnson chronicles how snipers took deadly aim at the Americans from rooftops and windows, prompting violent responses from Scott’s men. Mexican deserters and released convicts caused havoc in the streets. On the first night of occupation, American sharpshooters killed about 50 armed Mexicans. While hardly a 19th-century Battle of Mogadishu, in which Somalis bled American Rangers and special operations forces in desperate street fighting, the sporadic shooting in Mexico City after its occupation nevertheless illustrated the danger inherent in urban warfare. The battle fought by Gen. Zachary Taylor’s army at Monterrey also proved the immense danger of fighting street-to-street and house-to-house. In the final tabulation, the Americans counted some 2,700 casualties — of whom 383 were dead. Occupation lasted nine months, during which Scott secured his line of communication and supply to Vera Cruz, refitted his army, and evacuated the wounded.

When Gen. William Sherman and his 62,000-man Army of the West marched from Atlanta, Georgia, to the sea and captured Savannah in December 1864, observers the world over hailed the march as the greatest military feat since the days of the Duke of Marlborough. Indeed, for his logistical and operational brilliance Sherman won acclaim in Northern and European press. His men had won a decisive campaign that covered some 300 miles, established a new base of operations on the coast (which Sherman himself had identified as the chief purpose of his march), and crippled the Confederacy. In comparison, the U.S. Army under Scott — seldom more than 10,000 strong on the march to Mexico City, and approximately one-fifth the fighting strength of Sherman’s army — traversed almost this same distance in 1847. It did so in a foreign country, with less reliable intelligence, and lacking topographical information. (In contrast, Sherman had long been familiar with Southern culture, Southern cities, and the terrain his men traversed as they marched to the sea.) The U.S. Army under Scott accomplished all of this among a foreign people, in a harsher climate, and with a longer line of supply, all the while waging war against guerrillas. In spite of these difficulties, Scott’s army triumphed over a force three times its size. Looking back on his experience with Scott’s army many years later, no less a military giant than Ulysses Grant — Sherman’s trusted friend and confidant — described Scott’s campaign plan and execution, down to the level of tactics, as “faultless.”

Unlike the American Civil War that followed it, which in its conduct and character was at once Napoleonic and modern, the Mexican-American War was an old-fashioned conflict. Steamships in 1846 were comparatively new technology. No railroad could move men or supplies to Mexico (even in the United States, one could not travel contiguously across the South from the Mississippi River Valley to the Atlantic coast by locomotive until 1858). The iron horse would not find suitable military use in Europe until the Second War of Italian Unification (1859 to 1861). Even then, its success was modest. In Mexico, the U.S. Army moved many of its supplies by pack mule convoys. Though it sometimes strikes students of modern warfare as anachronistic, antiquated, and perhaps even odd, the Mexican-American War was not easier to plan, fight, and win simply because it occurred long ago, or because it seems quaint to planners in the historical present. While the linear tactics, field howitzers, and .69-caliber flintlock muskets of that conflict may strike us as primitive, the absence of modern technology made the war as difficult — and perhaps more so — to plan and win than later struggles in which more advanced military technology found widespread use. Then, as now, the projection of landpower over vast distances required immense skill and entailed great difficulty.

Today, the Mexican-American War is little more than a footnote to history. In taking the measure of the conflict’s place in the broader sweep of American military history, it is overshadowed by the U.S. Army’s experience in the Civil War. Some have suggested that the war in Mexico functioned as a mere laboratory of military science and as an environment and theater of preparation for the Civil War. Historian Alfred Hoyt Bill gave expression to this view in describing the Mexican-American War as a Rehearsal for Conflict.

For these reasons, and because of the antiquated nature of the conflict, students of military history and practitioners of war have, with few notable exceptions, neglected the important lessons of Scott’s Mexico City campaign, which tested the fighting ability of the U.S. Army like no previous war, and which put tremendous strain on American logistics and supply. Practitioners often forget that, in 1846, enlightened opinion among foreign observers was that the maturing American nation faced long odds for success in a war with Mexico. The geographical expanse of the country, its harsh environment, and its modern, European-style army would be more than sufficient, foreign commentators opined, to vanquish the American military. Scott’s march to Mexico City changed all that, and it established the audacity, professionalism, and proficiency of the U.S. Army as had no campaign before. Military success in Mexico, as Wayne Wei-siang Hsieh has written, was “the Old Army’s vindication.”

As planners look to the future, they should acknowledge not the differences that exist between the nature of modern warfare and the historical particulars of Scott’s campaign — which are apparent even to untrained eyes — but rather to continuities in the character of warfighting that have endured through time. They should seek to link the exigencies of campaigning in the 21st century to the ground truths of military necessity as Scott encountered them. American war planners and design experts will not face another Mexican-American War, but they will doubtless encounter, as Daniel T. Canfield has written, conditions that require alacrity of deployment, the mobilization of a robust reserve element, and the projection of landpower on a faraway continent that will require seaborne sustainment. They will confront, without fail, “a shrewd and determined enemy employing a hybrid combination of conventional and irregular threats.” In Mexico, combined American forces under Gens. Scott, Zachary Taylor, and Stephen Kearney numbered 30,000 — 0.4 percent of the Mexican population — and yet were expected to keep the peace with some 7 million inhabitants. So, too, in years to come, American servicemembers “will be outnumbered on most future battlefields and will almost certainly find themselves dwarfed by an ambivalent or potentially hostile indigenous population.” How can military planners draw from the past and prepare for this future conflict? Perhaps more important: How will they plan to win?

The Mexico City campaign still has much to teach American war planners. Indeed, as was written in the book of Ecclesiastes thousands of years ago, so still it should be said, “the thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.”

 

 

Mitchell G. Klingenberg, Ph.D., is a military historian in the Department of Military Strategy, Planning, and Operations and the School of Strategic Landpower at the U.S. Army War College. The views expressed in this article are his and do not necessarily reflect the official views of the U.S. Army War College, the U.S. Army, or the Department of Defense.

Image: Lithograph by N. Currier, Yale Collection of Western Americana