The Forces of Manifest Destiny (1846–1860)


An armada of U.S. warships floated in the choppy waters near Veracruz, a bustling port on the Gulf of Mexico. General Winfield Scott, the aging commander of U.S. forces in 1847, stood at the prow of the steamer, the U.S.S. Massachusetts. He gazed upon the city spires and mountain peaks, as he pondered his plans to “conquer a peace.” The sounds of the thundering surf and the blustering winds gave warning of an impending “norther.” After riding out the storm, he issued the order to commence landing his troops on Good Friday.

The morning of March 9 dawned bright and clear, while Scott's flagship steered toward the shorefront. The decks of the transports thronged with soldiers preparing to disembark. The officers ordered the enlisted men to pour fresh water into their canteens. Each carried rations for two days in a haversack, along with blankets and overcoats. Some packed an elocution primer titled the United States Speaker, which contained patriotic oratory by great Americans. Their smoothbore muskets and shiny bayonets flashed in the sunlight. The sounds of jingling spurs and rattling sabers filled the air. With the roar of a cannon shot at 2:00 p.m., the regimental bands struck up “Yankee Doodle,” “Hail Columbia,” and “The Star-Spangled Banner.” After climbing down the sides of the transports, the landing parties rowed surfboats to the beach.

Bobbing in the surfboats, the nauseous men told jokes to pass the time. One compared the experience to “seeing the elephant.” The euphemism referred to an old farmer, who heard that a circus was coming to town. Intrigued by the “humbug,” he loaded wagons with goods and hitched a team of horses. When he neared a parade led by an elephant, his team bolted, his wagon capsized, and his goods spilled everywhere. “I don't give a hang,” the American howled in the punch line, “for I have seen the elephant!”

The Americans rowed their surfboats through the waves that afternoon. They jumped into the knee-deep water near the beach and dashed toward the sand hills, which stretched a few hundred yards inland. Without a single loss of life, more than 5,500 landed safely by 5:30 p.m. A day later, the number ashore had escalated to 12,000.

Figure 6.1 Nathaniel Currier, Landing of the American Forces under General Scott, 1847. Prints and Photographs Division, Library of Congress


Throughout the antebellum period, an ideological compulsion for national expansion placed the armed forces of the U.S. in harm's way. John O'Sullivan, the editor of a New York magazine called the Democratic Review, extolled “our Manifest Destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.” The rhetoric gave voice to the notion that God chose the American people to extend their dominion from the Atlantic Ocean to the Pacific Ocean. The Mexican government, which controlled vast stretches of territory west of the Rocky Mountains, stood in opposition to America's professed mission.

American proponents of Manifest Destiny viewed transcontinental growth as a panacea for national security. Southern politicians demanded Texas annexation to extend the sphere of the slaveholding states, while northern leaders wanted to reduce the claims of the British Empire in the Oregon Territory. Democrats rallied in 1844 behind the presidential candidacy of James K. Polk, a former Speaker of the House and governor of Tennessee. On the road to the White House, he declared: “Fifty-four Forty or Fight!” The new commander-in-chief vowed to reassert the core principles of the Monroe Doctrine “with greatly increased force.”

Whereas the Monroe Doctrine warned the European powers not to intervene in the western hemisphere, the Americans distinguished themselves for years with their insatiable appetite for more land. They long deemed the Indian nations of North America as obstacles to the march of freedom, while boundaries meant little to an armed citizenry moving westward. Most foreign observers agreed with the London Times, however, that the American military represented no match for the armed forces of Mexico. Almost no one imagined the prospect of the U.S. flag flying over the capital city of another country.

American Blood

By the early 1840s, the chief concern of American policymakers had become the acquisition of Texas. The Lone Star Republic established relations with Great Britain and France, which raised concerns about national security in Washington D.C. Even though the Senate decisively rejected an annexation treaty with Texas, both chambers of Congress passed a joint resolution in favor of adding the state. Texas formally entered the Union on December 29, 1845.

The annexation of Texas prompted Mexico to cease diplomatic relations with the U.S. The government in Mexico City deemed the extension of American borders as nothing less than an act of war. Although Texans preferred the Rio Grande River as a southern boundary, the Mexican state of Coahuilla claimed a 90-mile strip of land stretching northward to the Nueces River. Leaders on both sides also claimed the valley of the Rio Grande north of El Paso, where no Anglo-American settlements existed. Polk offered to settle the boundary dispute, but he privately vowed to acquire more territory as far west as California.

Meanwhile, Polk favored negotiations with Great Britain concerning the permanent boundary of the Pacific Northwest. In spite of his combative rhetoric regarding the British, he decided to focus on securing Puget Sound and the Columbia River. During 1846, London offered to extend the U.S.–Canadian border along the 49th parallel to the Pacific Ocean. Secretary of State James Buchanan quickly negotiated the Oregon Treaty, which the Senate ratified on June 18. The handling of the Oregon controversy alienated many northerners, who grew wary of southern schemes for the acquisition of territory from Mexico.

By the spring of 1846, negotiations between the U.S. and Mexico had failed to resolve their boundary dispute. The Polk administration sent former Louisiana congressman, John Slidell, on a mission to Mexico City to offer millions of dollars for a territorial cession that included California. However, he returned to Washington D.C. without a deal. As war fever rose that year, the Mexican presidency changed hands four times. General Mariano Paredes y Arrillaga seized power and insisted upon Mexico's claim to Texas. Thomas O. Larkin, the American consul in Monterey, leaked word that the people of California “would be received as brethren” by their eastern neighbors. The U.S. Navy's Pacific Squadron received fore­warning to seize West Coast ports if war with Mexico erupted. Polk intended to achieve his expansionist aims one way or another.

At the urging of Polk, Secretary of War William Marcy sent American troops into the disputed border area of Texas. Known as “Old Rough and Ready,” General Zachary Taylor led a force that he named the Army of Occupation to the Nueces strip. His career spanned nearly four decades of military service, which earned him due respect. Stories circulated about his coolness in the Texas heat, as he sat atop his beloved horse, Old Whitey, with a tattered straw hat upon his head. He camped on a sandy plain near the hamlet of Corpus Christi, where their numbers eventually swelled to 4,000. While reveling in the debauchery of the town, U.S. forces paraded and drilled. Taylor's command included almost half of the regular Army by early 1846.

That March, Taylor led them to the east bank of the Rio Grande. Across the river from Matamoras, he erected Fort Texas and mounted siege guns. He also ordered a blockade at the mouth of the river. General Pedro de Ampudia delivered an ultimatum for the Americans to leave, but the Mexican government dispatched the more aggressive General Mariano Arista to replace him. The latter commander sent 1,600 cavalrymen across the river on April 25, when they ambushed a patrol of 63 dragoons under the command of Captain Seth Thornton. They killed 11 Americans while wounding five more. They captured Thornton along with the rest of his men. A few days later, Taylor wrote the War Department with the news: “Hostilities may now be considered as commenced.”

While Taylor called upon the governor of Texas to raise four regiments of volunteers, he marched the bulk of the Army regulars to Point Isabel for resupply. He left Major Jacob Brown behind with the 7th Infantry to defend Fort Texas from a possible siege. Arista led his army of 4,000 across the Rio Grande, while the guns at Matamoras opened fire on the American outpost the next morning. Taylor attempted to return to Fort Texas by road, but Arista intercepted him on May 8 at a pond called Palo Alto.

In the Battle of Palo Alto, the Mexicans outnumbered the Americans nearly three to one. With a chaw of tobacco in his cheek, Taylor sat sidesaddle on Old Whitey to watch the fight unfold. Major Samuel Ringgold directed the “flying artillery,” which represented an innovative use of light 18-pounders transported on carriages. Artillerymen rode horses swiftly into the chaparral and dismounted to unlimber their guns. They fired barrages of shell, shot, and canister on the enemy's infantry and cavalry, including their mounted lancers. Before sunset, Arista withdrew from the burning field. Taylor claimed victory, though he lost Ringgold that day.

The next day, Taylor pursued Arista 6 miles down the road to a dry riverbed called Resaca de la Palma. Owing to the narrow ponds and thick chaparral, he doubted the effectiveness of the “flying artillery” against the entrenched Mexican lines. That afternoon, the fighting evolved into a collection of small-unit actions. A detachment of dragoons under Captain Charles A. May galloped forward to confront the Mexican artillery. Taylor turned to Lieutenant Colonel William G. Belknap of the 8th Infantry Regiment and demanded: “Take those guns and by God keep them!” The Americans charged the battery with ferocity and defeated their foes in hand-to-hand combat. During the Battle of Resaca de la Palma, the Mexican soldiers panicked in the battlefield and fled to Matamoras in a rout.

Figure 6.2 The U.S.–Mexico War


The success of Taylor's forces brought relief to the defenders of Fort Texas, although Brown died during the siege. Consequently, General Order 62 renamed the outpost Fort Brown in his memory and gave birth eventually to an American town named Brownsville. As a result of the fighting at Palo Alto and Resaca de la Palma, the Americans reported 34 deaths and 113 wounded. In contrast, their foes suffered as many as 1,200 killed and wounded in action. In the high chaparral, the wolves and the vultures feasted before the gravediggers buried the corpses. Many Americans witnessed the horrors of war for the first time.

With Americans engaged in battle, the Polk administration approved the draft of a war message in early May. Taylor's report about the Mexican attack on Thornton's patrol arrived after the cabinet had already decided to seek a formal declaration of war. On May 11, Polk's written message to Congress asserted that a state of war existed between the U.S. and Mexico. His justifications included the “grievous wrongs perpetrated upon our citizens” over the years by “reiterated menaces.” The most recent attack by the Mexican army, he declared, “shed American blood upon the American soil.” He asked for the “immediate appearance in arms of a large and overpowering force,” which he intended to use to bring “the existing collision with Mexico to a speedy and successful termination.”

Two days later, Congress effectively declared war. The war bill passed the House 173 to 14, although the debate lasted only a half-hour. Among the “Immortal Fourteen” in opposition, ex-president John Quincy Adams, now a Whig congressman, denounced the decision of the Democratic majority. The Senate took a bit longer but gave approval with a 40 to 2 vote. Senator John C. Calhoun, a former Secretary of War, abstained from voting, saying that he would not agree to make war on Mexico “by making war on the Constitution.” Claims that the commander-in-chief misled Congress eventually gave rise to the nickname, “Polk the Mendacious.”

On to Mexico

Polk entered the war with one object clearly in view – to seize all of Mexico north of the Rio Grande and the Gila River while extending the U.S. border to the Pacific. Congress authorized him to call for 50,000 volunteers and immediately appropriated $10 million for national defense. Though he envisaged a limited war of short duration, he kept numerous options on the table. On May 13, 1846, he discussed his military objectives with Secretary of War Marcy and General in Chief Scott during a meeting at the White House. Polk offered Scott “command of the army to be raised,” which he accepted.

After the meeting with Scott and Marcy ended, Polk turned to Senator Thomas Hart Benton of Missouri for military advice. Benton, a Democrat, wanted to put Scott, a Whig, on the shelf. Accordingly, he attached an amendment to a pending military bill allowing the commander-in-chief to appoint two new major generals to the regular Army. Despite not having worn the uniform for over three decades, the senator wanted one of the appointments for himself. However, the House of Representatives reduced the authorization of commissions to only one major general. Whatever Benton's ambitions, Polk felt obligated to promote Taylor to the senior rank while commanding U.S. forces in Mexico. The War Department expected the old soldiers to just fade away in time, but Scott remained in Washington D.C. to make arrangements and preparations for the military campaigns.

With the military campaigns in motion, Polk and Secretary of the Navy George Bancroft considered a secret plan to end the war as quickly as possible. They sent instructions to Commodore David E. Conner, commander of the Home Squadron patrolling the Gulf of Mexico. That summer, he allowed General Antonio López de Santa Anna, a former president of Mexico, to return from exile in Cuba. The “Napoleon of the West” previously sent a message through an associate to the White House, saying that “a treaty can be made.” Owing to the back-channel communications, he disembarked at Veracruz “without molestation” by the Navy. However, he decided to renege on any promises made to the gringos. Eventually resuming power in Mexico, Santa Anna raised an army of 20,000 men and marched toward San Luis Potosí.

Entering Mexico from the north, Taylor crossed the Rio Grande with small boats and heavy mortars. Arista withdrew from Matamoras on May 18, as Taylor took control of the town. The Americans provided medical care for the patients in the hospitals and avoided disrupting civilian affairs. To avoid clashes between U.S. soldiers and the townspeople, Taylor maintained his headquarters and his units outside Matamoras.

American volunteers arrived in mass at Point Isabel and quickly joined Taylor's army on the Rio Grande. Although the Mexican army in the field outnumbered them, U.S. forces possessed a superior arsenal. For example, Samuel Colt of Hartford, Connecticut, devised firearms with a revolving cylinder that locked into alignment with a fixed barrel. The mounted troops often wielded percussion rifles, while most infantrymen carried flintlock smoothbore muskets. Noted for their contempt of Mexicans and Indians in the borderlands, a special regiment known as the Texas Rangers wore a belt of pistols around their waists. The states of Louisiana, Mississippi, Alabama, Georgia, Tennessee, Maryland, and Ohio raised thousands of better-armed soldiers, who filed across the border into Mexico.

At the age of 24, Lieutenant Rankin Dilworth of Ohio deployed to Mexico that summer. A graduate of West Point, he began keeping a diary shortly before arriving on the Rio Grande. Like many of his comrades, he wanted to “see the elephant” on the other side. He waxed romantic about the strange and exotic landscape, which looked nothing like the places he knew back home. His passages referred to a girl he left behind, but they also took note of beautiful senoritas near the Army camp outside Matamoras.

That August, the Army moved hundreds of miles downriver to camp at Camargo. On the journey, the troops occasionally went ashore to gather wood. The banks teemed with snakes, tarantulas, ants, and scorpions at almost every turn. To their surprise, the Mexicans greeted them with afandango – an open-air dance marked by fiddling, gambling, smoking, and drinking. However, tempers flared after one American volunteer stole another's catfish. Misery followed the Army to Camargo, where one out of every eight perished from disease.

Marching overland from Camargo to Cerralvo, U.S. soldiers anticipated “mucho fandango” in Monterrey. In mid-September, Taylor divided nearly 6,220 troops into two wings to attack the fortified city from opposite sides. General William J. Worth led a division from the west to sever the city's road to Saltillo, while Taylor ordered the main body to attack from the east. Under the command of Ampudia, more than 7,000 Mexican soldiers opposed the assault. A citadel dubbed the “Black Fort” belched cannonballs from the north side of the city. Under a hail of Mexican artillery and musket fire, the Americans entered the city's outskirts and maneuvered through the narrow streets. They fought house to house, battering down doors with planks. Eventually, General John Quitman's brigade captured the Mexican batteries at El Teneria redoubt and turned the guns on the fleeing enemy. Mexican forces rallied in the central plaza, where U.S. howitzers blasted them with indirect fire. On the morning of September 25, Ampudia agreed to an eight-week armistice and to evacuate the defenses. As the Mexican divisions marched out of Monterrey, they left behind a “vast cemetery” of unburied corpses.

The Battle of Monterrey produced 561 American casualties, including Lieutenant Dilworth from Ohio. The last entry of his diary appeared shortly before he experienced his first action, when a cannonball tore off one of his legs. He perished a few days later. Because his family lacked the money to pay for the return of his body, the Army buried him in Monterrey.

The news of an American victory at Monterrey stirred no pride in the Polk administration. Instead, the cabinet admonished Taylor for the “great error” of offering lenient terms to Ampudia. If Taylor had captured the opposing forces, some members opined, then “it would have probably ended the war with Mexico.” While settling on a plan for “masterful inactivity” south of Monterrey, Polk cancelled the armistice on October 11.

Polk turned his attention to the Gulf Coast, where the port of Tampico represented a military objective. On November 14, Commodore Conner entered the harbor and took control of the town. A week later, an American detachment from Brazos Island arrived by ship to secure the area. With more troops sent directly from the U.S. to strengthen the garrison, the war against Mexico expanded.

Unbeknownst to the troops in Mexico, the Polk administration eyed a larger prize. Benton convinced the commander-in-chief to authorize an expedition to seize the Gulf port of Veracruz. The base of operations, he surmised, would enable American regiments to march inland to capture Mexico City. If appointed lieutenant general of the invading army, then the senator offered to take command and to negotiate with Santa Anna himself. Pending congressional approval of the superior rank for Benton, Polk and Marcy decided to assign interim command to Scott.

Scott soon reached Camargo, while Taylor marched to Victoria. Their professional relationship soured thereafter, because the former removed a number of regiments from the latter's command. Despite the reduction in numbers, Taylor's army linked with a division under General John E. Wool and marched to Saltillo that winter.

On February 22, 1847, Santa Anna commanded close to 15,000 Mexicans in a battle that began on George Washington's birthday. Six miles south of Saltillo, Taylor directed 4,750 Americans to defend a mountain pass called Buena Vista. After reading a summons to surrender, he responded with eloquence: “I beg leave to say that I decline acceding to your request.” Unofficially, “Old Rough and Ready” told the Generalissimo “to go to Hell.”

As the sun rose the next morning, a slight drizzle fell upon the colorful lines that formed on the plateau. Mexican cavalry and infantry assailed the American flanks with deliberate movements, while the main body launched a direct assault against the center. Heavy fire from U.S. batteries turned the tide of battle. Their volleys of grape and canister halted the advancing enemy, while the Mississippi dragoons of Colonel Jefferson Davis withstood a series of massive charges. A sudden thunderstorm delivered rain and hail that afternoon, but the Americans held their ground and forced the Mexicans backward.

The two armies stood a few hundred yards apart in one of the fiercest fights of the war. Hour after hour, the sounds of screaming soldiers, neighing horses, cannon fire, and musket balls filled the mountain air. The pungent odors grew unbearable with the smell of burning flesh, including dead and rotting animals. As clouds of gun smoke drifted across Buena Vista, the fog of war shrouded almost everything by dusk.

After the Battle of Buena Vista ended, Santa Anna withdrew his exhausted troops southward to San Luis Potosí. The Mexican army suffered more than 1,800 casualties, while U.S. forces counted 264 killed, 456 wounded, and 23 missing in action. Instead of pressing onward, Taylor returned to Monterrey in victory. American newspapers compared him favorably to Generals Washington and Jackson, but Buena Vista was his last battle in Mexico.

Forward March

The northern boundaries of Mexico encompassed a land of a thousand deserts. With inhabitants concentrated along the Rio Grande, near the Wasatch Mountains, and on the Pacific Coast, foreign observers noted large strips that appeared virtually ungoverned. For years, British officials threatened to seize California in order to curb the transcontinental ambitions of the U.S. If Americans did not overrun Mexican territory, Polk feared that the European powers would establish a foothold west of the Rocky Mountains.

Even before the war began, Polk sent First Lieutenant Arnold H. Gillespie of the Marine Corps as a “special agent” into Mexican territory. After traveling across Mexico, he boarded a U.S. ship at Mazatlán and sailed to California. He delivered messages to Larkin, the American consul, and to Commodore John D. Sloat, the commander of the Pacific Squadron. He also carried secret letters to Captain John C. Frémont, the son-in-law of Benton and a celebrated leader of topographical expeditions. Eventually, they met on the shores of Upper Klamath Lake.

Whatever they discussed, much of California teetered on the brink of revolt. Native Californios such as General Mariano Guadalupe Vallejo in Sonoma believed that their economic interests no longer tethered them to Mexico City. Even more belligerent, hundreds of rowdy Americans resided at Sutter's Fort on the Sacramento River. The Pacific Coast appeared ready to gravitate into the orbit of the U.S.

On June 14, 1846, a group of 40 men from Sutter's Fort assailed the town of Sonoma. William B. Ide, a settler from Vermont, led them. After proclaiming the independence of the “California Republic,” they hoisted a flag with a grizzly bear and a single star painted on a white cloth. Frémont returned to the Sacramento Valley, although the Mexican authorities had previously ordered him to leave. Among the instigators of the Bear Flag revolt, he agreed to lead a battalion southward to conquer all of California.

Less than a month later, Commodore Sloat steered the Pacific Squadron to the northern coast of California. Alarmed by rumors that a British fleet approached, he sent sailors and marines ashore at Monterey and Yuerba Buena. They raised the Stars and Stripes and claimed California on behalf of the U.S. His actions prompted the Bear Flaggers to join the U.S. forces, though the aging officer soon retired from command.

His successor was Commodore Robert F. Stockton, who resolved to seize southern California that summer. To cut off retreating Mexican forces under General José Castro, Stockton sent Frémont by ship to San Diego with the “California Company of mounted riflemen.” Landing at San Pedro, Stockton dispersed Castro's soldiers along the coast with a “gallant sailor army.” Within days, Stockton and Frémont occupied Santa Barbara and Los Angeles. On August 17, they announced that all of California belonged to the U.S.

Meanwhile, Colonel Stephen W. Kearny led the Army of the West on one of the most remarkable marches in American military history. At Fort Leavenworth, he outfitted 1,600 soldiers from the First Dragoons and the Missouri volunteers. During the summer of 1846, they set out on the 780-mile Santa Fe Trail. Though hardships abounded, they traveled about 20 miles a day to reach the Raton Pass. As Kearny approached unopposed from the north, the governor of New Mexico, Manuel Armijo, decided to flee southward. On August 18, Americans captured Santa Fe without firing a shot. They erected Fort Marcy while establishing a set of laws known as the Kearny Code. “General Kearny,” Polk remarked upon reading a dispatch from New Mexico, “has thus far performed his duties well.”

After leaving volunteer regiments in New Mexico, Kearny marched 300 dragoons to the far west. Beginning in September, they journeyed nearly 1,000 miles across a landscape of extremes. At Socorro, they met a party led by the “mountain man” Christopher “Kit” Carson, who reported that U.S. forces already occupied California. Retaining 100 dragoons in his command but sending the rest back to Santa Fe, Kearny pressed westward with Carson as a guide. At the junction of the Gila and the Colorado Rivers, they learned that a Californio insurgency had thrown off the “Anglo-Yankee yoke” from Los Angeles to Santa Barbara. Nearly 40 miles from San Diego, the exhausted dragoons made contact with a small party led by Gillespie and Lieutenant Edward Beale of the Navy. The Americans reconnoitered the area and readied for battle near the Indian village of San Pascual.

The Battle of San Pascual began on December 6. At 2:00 a.m., Kearny directed a column to conduct a headlong attack on a mounted band of Californios. However, 160 lancers suddenly turned and charged their line in the darkness. The cavalry sabers and naval cutlasses proved ineffective against the long lances. A charging lancer wounded Kearny in the groin, while Gillespie received a mark on his face. With 18 dead and 13 wounded, the Americans clung to Mule Hill for days. Kearny sent Beale with Carson and an Indian to San Diego for help. Eventually, a detachment of 180 sailors and marines rescued Kearny's desperate command.

Following his arrival in San Diego, Kearny joined with Stockton in an effort to recapture Los Angeles. Shortly after the New Year began, a joint force of sailors, marines, and dragoons reached the mission of San Luis Rey. On January 8, 1847, they engaged 350 Californios at the San Gabriel River just 12 miles from Los Angeles. On the anniversary of Andrew Jackson's victory at New Orleans, the Battle of San Gabriel lasted less than 90 minutes. Next, the opposing sides skirmished at La Mesa. U.S. forces suffered one dead and 13 wounded from the two confrontations. The Californios evacuated Los Angeles, thereby leaving the town to the Americans. A week later, Frémont reappeared with a battalion of soldiers, a number of cannons, and the Treaty of Cahuenga. Weary of the hostilities, Stockton recognized the treaty and appointed him as governor of California. Kearny protested to no avail, though he later demanded a court martial of Frémont for insubordination. Despite the bickering among the American officers, the Californio insurgency melted away.

The Americans in New Mexico faced an insurgency as well. The civilian governor, Charles Bent, underestimated the discontent in Santa Fe and beyond. In early 1847, a drunken mob in Taos decapitated him at home. Violence spread quickly from pueblo to pueblo. On February 3, Colonel Sterling Price led a battalion to Taos and crushed the insurgents with ferocity. Thereafter, the population of New Mexico tolerated U.S. control.

Before the revolt in New Mexico, a thousand Missouri volunteers commanded by Colonel Alexander W. Doniphan marched southward along the Rio Grande. A towering lawyer from Liberty, Missouri, he skirmished with Indian tribes along the way. He did not fear “the Devil or the God that made him,” or so his men believed. During late 1846, they defeated a larger Mexican battalion commanded by Colonel Antonio Ponce de León in the Battle of the Brazito. After storming El Paso, the Americans turned toward the city of Chihuahua.

On the road to Chihuahua, Doniphan's march encountered significant resistance near the Sacramento River. On February 28, 1847, General García Condé opposed the Americans with close to 3,000 Mexicans. Using unconventional tactics, Doniphan overwhelmed Condé's dispositions along a plateau. Only one American perished in the Battle of the Sacramento, but the Mexicans suffered hundreds of deaths that afternoon. Doniphan took possession of Chihuahua a few days later.

From Chihuahua to Sonoma, U.S. forces occupied Mexican territory without losing a major battle. Across a thousand deserts, Americans in uniform accomplished feats of strength that prompted comparisons with the legends of the ancient world. Few expected to rest on their laurels, because Mexico City remained unconquered.

War at Home

U.S. victories on the battlefields failed to silence the carping in regard to “Mr. Polk's War.” Although their arguments varied, many Whigs expressed misgivings about the armed conflict from the outset. Even some Democrats privately suspected that the president had manufactured the hostilities with Mexico. Nonetheless, the dispatches of war correspondents on the front lines raised public interest in the anticipated spoils of Manifest Destiny.

On a hot night in the summer of 1846, Congressman David Wilmot, a Democrat from Pennsylvania, sparked a fiery debate about Manifest Destiny that consumed the country for years. As a supporter of a “necessary and proper war,” he wanted to secure “a rich inheritance” in North America for the people “of my own race and own color.” He proposed an amendment to a wartime appropriation bill stating that “neither slavery nor involuntary servitude shall ever exist” in territory acquired from Mexico.

Labeled the Wilmot Proviso, the amendment encouraged kindred spirits from the northern states to set aside party affiliation for an ideological goal. “I make no war upon the South,” Wilmot insisted, although his proviso promised to stop the spread of the slave labor system into New Mexico and California. The House of Representatives passed the bill as amended, but the Senate took no action in regard to “free soil.” In subsequent months, more appropriations bills passed through the House with the Wilmot Proviso attached. Eventually, southern slaveholders in the Senate filibustered measures that prevented U.S. citizens from “emigrating with their property.” Sectional interests divided Congress during the war, splintering the caucuses of both the Whigs and the Democrats.

As the discontent in Congress grew, a first-term Whig from Illinois named Abraham Lincoln introduced another controversial resolution. When running for office during 1846, he asked the citizen soldiery of his pro-war district to “secure our national rights” by volunteering for military service in Mexico. After arriving in Washington D.C., though, he denounced the commander-in-chief as “a bewildered, confounded, and miserably perplexed man.” He demanded to know the exact location on Texas soil where American blood was shed. The “spot resolutions” won him accolades from fellow Whigs, even if they achieved little else. As a result, colleagues in the chamber derided the little-known lawyer with the nickname “Spotty.” Unhappy Illinois constituents made Lincoln a one-term congressman.

Though fanning the flames of sectional animosity, a majority in Congress endorsed the transcontinental visions of an American republic. Opponents of the war slandered Polk as a tool of the “Slave Power,” while antislavery politics enhanced the popular cravings for Mexican lands west of the Rocky Mountains. The Mexican War Bounty Land Act, a measure passed by Congress on February 11, 1847, promised a federal land warrant of 160 acres for veterans. With the sale of additional sections, the auctions of the General Land Office would help to raise revenue for financing the war debt. Consequently, Secretary of the Treasury Robert J. Walker lobbied Congress to create the Interior Department for the proper disposal of the national domain to all citizens. Upon completing their military service, scores of Americans expected to feast upon the “free soil” of the far west.

While praising the gallantry of Americans in uniform, Polk pledged to secure “ample indemnity” for their prolonged struggle in Mexico. Once again, he attempted to bestow supreme command upon Benton with another defense authorization bill. In early 1847, the commander-in-chief commissioned the senator as a major general. Irrespective of the doubts about his military competence, he could not go to Mexico unless Scott and Taylor were recalled from duty. Moreover, Senator Sam Houston of Texas announced that he – not Benton – deserved the commission. Given the rancor in Congress, Benton decided to decline the president's offer.

Foiled by congressional sniping, the president assembled his cabinet to select a special emissary to negotiate peace with Mexico. Secretary of State Buchanan seemed a logical choice, but he asserted that administrative duties in Washington D.C. required his full attention. To join Scott in Mexico, he suggested appointing the chief clerk of the State Department, Nicholas P. Trist. Buchanan's most trusted deputy possessed impressive credentials, including honors from West Point and fluency in Spanish. On April 10, Trist agreed to sail immediately for Mexico with the working draft of a treaty in his hands.

Whereas the partisan press clamored for peace with Mexico, an outpouring of romantic literature deepened America's attachment to the war. Herman Melville, a young novelist, crafted a series of satirical articles about the indefatigable Taylor known as “Authentic Anecdotes of Old Zack.” The aging James Fenimore Cooper penned a suspenseful novel titled Jack Tier (1848), which recounted a plot among traitors attempting to supply Mexicans with gunpowder. In a collection of poems called Lays of the Palmetto(1848), William Gilmore Simms scribbled odes that compared a South Carolina regiment to chivalrous knights. Though evoking a racist tone, the Boston abolitionist James Russell Lowell wrote verses called The Biglow Papers (1848) that irreverently lampooned the clash of arms. A variety of theatrical melodramas played to cosmopolitan crowds, who cheered the depictions of the exotic landscapes as well as the action heroes of the war.

The news of the war stirred the passions of writer Henry David Thoreau of Concord, Massachusetts, even while living in a cabin at Walden Pond. Enraged by the call for volunteer soldiers, he went to jail for refusing to pay his state taxes. His act of protest seemed futile to his peers, because the tax in question did nothing to underwrite “Mr. Polk's War.” A single night in jail inspired him to compose a provocative essay titled “Civil Disobedience,” which later broadened the appeal of non-violence to the American people.

The Halls of Montezuma

With U.S forces in control of northern Mexico, Scott planned a bold operation on the Gulf Coast. The 60-year-old took command of the largest amphibious assault ever attempted in history at that time. “Providence may defeat me,” Scott wrote to Taylor after arriving in Mexico, “but I do not believe the Mexicans can.”

During the early months of 1847, Scott amassed close to 12,000 troops south of Tampico on Lobos Island. In New Orleans, Quartermaster General Thomas S. Jesup purchased and leased vessels, wagons, and animals for use by the Army. Commodore Conner maintained the blockade of the Mexican coastline from his headquarters at Anton Lizardo. U.S. brigs, barks, sloops, and schooners provided transportation across the Gulf of Mexico. Navy crewmen also operated specially designed surfboats, which ferried Army personnel and supplies from the ships to the shores. On March 2, Scott's flotilla sailed toward Veracruz.

Scott's flotilla steered away from the island fortress opposite Veracruz named San Juan de Ulúa. While approaching Collada Beach to the south, they avoided the Mexican guns in addition to the neutral British and French ships offshore. On March 9, the troops disembarked on the undefended beach with remarkable speed. Proceeding inland, they formed a trench line about 2 miles below the city. Scott sent several divisions around the landward defenses to invest a perimeter, which stretched as far north as Vergara. They also blocked the water supply for 15,000 residents and 3,360 Mexican soldiers.

The Mexican batteries shelled the American dispositions, while Scott toured his forward lines. Spotting his men exposed to fire, he bellowed: “Down – Down, men!” One of them crouched behind a parapet and shouted back: “But General, you are exposed.” He answered with a dramatic flair: “Oh, generals nowadays can be made out of anybody, but men cannot be had.”

With only light artillery for the initial siege, Scott requested assistance from Conner's successor, Commodore Matthew C. Perry. The Navy provided six big guns – three 32-pounders and three 8-inch Paixhans – for emplacement ashore behind the dunes. From March 24 to March 26, the heavier cannons bombarded the Mexican defenses. After the U.S. batteries ceased firing, General J. J. Landero agreed to surrender. Americans suffered only 80 casualties overall. To restrain soldiers and civilians at Veracruz, Scott imposed martial law with General Order 20.

With a base for operations secured, Scott wasted no time savoring his victory. He expressed concern about an outbreak of yellow fever, which locals referred to as el vómito. In order to escape the deadly hot season of the coast, he marched his troops westward to the highlands. He selected the National Road, which the Spanish conquistadores used as a route into the interior centuries earlier. Although Worth expected to assume the “position of honor,” Scott placed another division under General David E. Twigg on the vanguard.

Twigg advanced toward Jalapa, a city nearly 75 miles from Veracruz. His column included 2,600 infantry as well as several units of dragoons and artillery, but they moved slowly toward the city. His scouts reported the dispositions of Mexican soldiers along a mountain called Cerro Gordo, which some referred to as El Telégrafo. With close to 12,000 troops and 32 cannons covering the National Road, Santa Anna vowed to block the Americans at the key pass.

The Americans encamped by Plan del Rio, where Scott brought up reinforcements to raise his numbers to 8,500. Among his most trusted officers, Captain Robert E. Lee scouted the thick woods to locate the best path to reach the enemy's rear. He directed the engineers to clear a trail past Cerro Gordo without detection. On April 17, Twigg's infantry clashed with Mexican troops at a hill named La Atalaya. The blue-clad soldiers hauled a 24-pounder to the elevated position and began blasting the Mexican fortresses on the hilltops the next morning. Unable to protect his flanks, Santa Anna ordered his men to fight hand-to-hand. Twigg sent his division on a furious assault, while General Gideon Pillow commanded a brigade that hit the Mexican batteries on the left. The Battle of Cerro Gordo resulted in 417 American casualties, including 64 dead. Before falling back, the Mexican army lost more than 1,000 men. Santa Anna left behind his spare wooden leg, which a volunteer regiment from Illinois claimed as a prize.

While Santa Anna attempted to rebuild his decimated army, Scott marched his victorious one to Jalapa. However, the one-year term of enlistment for seven of his volunteer regiments neared expiration. Most departed for home that May, which reduced U.S. forces to 5,820 effectives. Because Mexican guerrillas along the National Road thwarted supply lines, the depleted units faced the prospect of living off the land. Scott soon advanced to Puebla, the second-largest city in Mexico, but the national capital remained 170 miles away.

For three months, Scott's army simmered in Puebla. Upon receiving news of Trist's appointment, the U.S. commander fumed that the Polk administration intended “to degrade me.” He sent a hasty letter to the War Department begging “to be recalled from this army,” though Marcy ignored the request at the time. In spite of his mortification, Scott devised a system for gathering supplies and intelligence while reinforcements matriculated into Puebla. That August, General Franklin Pierce of New Hampshire arrived with 2,400 soldiers for the final push to Mexico City. Scott's army became “a self-sustaining machine” of 14,000, which he reorganized into four divisions commanded by Worth, Twigg, Pillow, and Quitman. While training at Puebla, they prepared to confront more than 36,000 Mexicans under Santa Anna.

At the same time, Trist made contact with Santa Anna through a British agent in Mexico City. The Generalissimo demanded a bribe of $10,000 to begin negotiations and at least a million dollars upon the ratification of a treaty. Drawing upon available funds for his army, Scott procured an advance for Trist to make a payment as requested. However, Santa Anna pocketed the bribe while claiming that the Mexican Congress prevented him from treating with the Americans.

Beginning on August 7, the Americans departed from Puebla to enter the Valley of Mexico. Before them stretched the ancient realm of the Aztecs, which included a prehistoric lake bed surrounded by snow-capped volcanoes. With each division separated by a half-day's march, they met no opposition along the National Road. Standing on a ridge at the base of Popocatépetl, Scott saw “the gorgeous seat of the Montezumas” beyond the marshes and canals. Causeways sprawled from Mexico City like the spokes on a wheel, which seemed to invite him to attack. Santa Anna prepared to defend the national capital at El Peñon, but Scott moved around Lake Chalco to the Acapulco Road at San Agustín and advanced from the south. While harassing Twigg's division at Ayotla, the Mexicans established a new defensive line behind the Churubusco River.

To the southwest of Churubusco, General Gabriel Valencia extended his lines between the towns of Padierna and Contreras. Scott sent Pillow, Twigg, and Worth on a narrow muddy road that skirted a large lava bed called the Pedregal. They came under fire from Valencia, but several brigades pressed ahead on the morning of August 20. In the Battle of Contreras, Americans lost 60 killed and wounded in action. They routed Valencia's troops in only 17 minutes, slaughtering hundreds and capturing 813 prisoners.

Mexican troops commanded by Santa Anna kept their composure on the bridge at Churubusco, which stood 500 yards from the thick-walled San Mateo Convent. Among the most defiant soldiers at the river, the San Patrico Battalion included hundreds of Irish Catholic deserters from American regiments. That afternoon, they fired cannons and muskets at the advancing lines of their former comrades. U.S. forces prevailed in the Battle of Churubusco, because the bluecoats carried the works with a spectacular bayonet assault. Scott lost 1,053 casualties that day, while the dragoons galloped forward to the gates of Mexico City. Afterward, many of the San Patricos faced court martials and eventual execution. As the Americans gained momentum with each victory, Santa Anna lost a third of his army at Churubusco.

Withdrawing to the capital, Santa Anna decided to explore a truce with Scott. Eager to avoid more bloodshed, the latter penned an effusive note to the former decrying this “unnatural war between the two great republics of the continent.” Accordingly, both sides agreed to halt military actions and to permit Trist to meet with a peace delegation. Nevertheless, Santa Anna rebuilt his defenses in violation of the truce. After dismissing an American ultimatum, the Mexican dictator vowed to “repel force by force” that September.

On September 8, the Battle of Molino del Rey erupted. American intelligence reported that the old mill on the outskirts of Mexico City served as a foundry for the casting of cannons. Scott sent Worth's division to destroy the munitions, but Mexican resistance stiffened along a hill. After taking the stone buildings, U.S. soldiers overran the crumbling walls of the Casa Mata. However, Worth found no evidence of a working foundry. During two hours of bloody fighting, Scott's army lost 116 dead and 671 wounded.

Scott's army marched along the western causeways toward Mexico City. The rank and file gazed upon the Castle of Chapultepec, which served as the home of the Mexican military academy – the Colegio Militar. It loomed atop a hill nearly 200 feet above the marshlands, while Mexican troops lined the walls.

On the morning of September 13, Scott organized a feint by Quitman at the San Antonio causeway while sending Pillow's division directly against the hill. Their lines converged on the military objective with remarkable coordination. A heavy barrage by 24-pounders pummeled enemy dispositions at sunrise. Scaling parties that included 40 marines waded through the cypress marshes to enter the courtyard gardens. Nicknamed the “forlorn hope,” they climbed ladders to storm the castle. Lieutenant George E. Pickett of Virginia grabbed the Stars and Stripes from a wounded comrade, Lieutenant James Longstreet, and carried it to the top. The Americans slew the Mexicans unmercifully, though six cadets remembered as Los Niños Héroes plunged to their deaths rather than surrender their national flag. By 9:30 a.m., Chapultepec had fallen to U.S. forces.

After suffering nearly 800 casualties in the Battle of Chapultepec, U.S. forces penetrated Mexico City. They seized the gates of Belén and San Cosmé by nightfall. Santa Anna's troops dispersed in haste, which prompted him to curse that even if “we were to plant our batteries in Hell, the damned Yankees would take them from us.” The next day, Scott paraded his columns through the Grand Plaza in triumph. Marines hoisted the U.S. flag over “The Halls of Montezuma,” that is, the National Palace.


“They literally die like dogs,” observed Captain George B. McClellan, who lamented the agony of his comrades from Veracruz to Mexico City. While the U.S. lost 1,733 killed in action during the war, another 4,152 suffered wounds. The American death toll eventually reached a staggering 13,780, of which 11,550 perished from diseases. In other words, only one out of eight deaths for the American military derived from enemy blows.

Despite an unbroken string of victories during 1847, the American military lacked the logistical capabilities to effectively occupy the entire country. After 17 months of hard fighting, the troops appeared exhausted by maladies ranging from yellow fever to dysentery. One unit even dubbed themselves the “1st Diarrhea Rangers.” Some referred to their chronic ailments as “Montezuma's revenge.” Improper hygiene and poor healthcare diminished combat readiness, although for the first time military doctors began using anesthetics to treat patients. Owing to the parsimony of Washington D.C., Scott's army remained on foreign soil for several months without adequate food, clothing, and medicine.

On the day that he entered the Palace of the Montezumas, Scott urged U.S. soldiers to remain “sober, orderly, and merciful.” One of his major challenges involved the acts of insubordination by those under his command, which led to court martials for Worth and Pillow. While establishing martial law and quelling mob violence, he appointed Quitman as the military governor of the capital. In an old Spanish palace near the Grand Plaza, the Americans gathered to form a fraternity named the Aztec Club. Even the most belligerent adopted elements of Mexican culture, such as chewing-gum, cigarettes, and mustaches. In spite of carousing and scandals in certain quarters, the occupation of Mexico City proceeded with relative calm.

That November, the archbishop of Mexico, Juan Manuel, asked the U.S. commander to free Mexicans detained as prisoners. Before vacating power, Santa Anna ordered the release of convicts from the jails to encourage mob violence in the streets. In the absence of a legitimate civilian administration, Scott directed the marines to round up criminals. Furthermore, he collaborated with the clergy to protect the property of the Catholic Church. They established a parole process, whereby detainees swore an oath “before God our Lord and on this Holy Cross” not to take up arms. Within weeks, they worked out the release of the Mexicans in American hands.

For months, Mexican soldiers under Santa Anna continued to roam the countryside. Briefly, he organized an unsuccessful siege of the American garrison at Puebla. Guerrillas thwarted supply and communication lines to Mexico City, but they also looted towns and villages. Marching from Veracruz, General Joseph Lane led 2,500 Americans against the resistance at Huamantla near the National Road. With his support across Mexico collapsing, Santa Anna departed for Jamaica later that year.

Scott's army peaked at 15,000 effectives in Mexico, but for the most part they huddled inside the capital. Marcy authorized Scott to retaliate against the guerrillas with “the utmost allowable severity” while placing the burden of defense “to the utmost extent” upon the Mexican population. With the cost of the war approaching $100 million, he assessed a levy against Mexico for $3,046,498 as an “indemnity.”

Polk requested increased military funding from Congress that December, which seemed to buoy the hopes of the “All Mexico” movement. O'Sullivan, the editor who coined the phrase Manifest Destiny, trumpeted in the press: “More, More, More!” Within the administration, most cabinet members expressed an interest in expanding the war effort. In fact, Mexican leaders in the Yucatan appealed to the U.S. for assistance in suppressing an indigenous uprising across the peninsula. However, congressional opposition stymied an appropriations bill that raised 10 new regiments and additional volunteers for deployment to Mexico.

Disregarding the president's request for him to leave Mexico, Trist decided to resume peace talks at the urging of Scott and the British legation. After the Mexicans organized a new government, he attempted to deal with the commissioners. The main point of contention involved the borderline between the two nations. In early 1848, their negotiations culminated at the village of Guadalupe Hidalgo outside the capital.

Signed on February 2, 1848, the Treaty of Guadalupe Hidalgo set the final terms. Accordingly, Mexico recognized the Rio Grande as the boundary with Texas. Moreover, it ceded all the lands that became the states of California, Arizona, New Mexico, Utah, and Nevada as well as portions of Wyoming and Colorado. In return, the U.S. agreed to pay Mexico $15 million and to assume responsibility for the unpaid claims by Americans against the Mexican government. With the stroke of a pen, the war in Mexico officially ended.

A deputation of prominent citizens of Mexico approached Scott with an offer that he found difficult to refuse. After his recall by the War Department that February, the U.S. commander contemplated resigning his commission and accepting an appointment as the dictator of Mexico for four to six years. Likewise, he mused that the discharged veterans of his army might remain at his side if paid well by the elites. As the Mexican people learned “to govern themselves,” his transitional regime could manage the ports, arsenals, forts, and mines. He rejected the tempting offer, though, and soon returned to Washington D.C.

In Washington D.C., Polk hesitated but submitted the Treaty of Guadalupe Hidalgo to the Senate. “The extensive and valuable territories ceded by Mexico,” declared the president, constituted an “indemnity for the past” as well as a “guaranty of security for the future.” Following Senate ratification of the treaty on March 10, the Mexican government officially concurred two months later. That summer, American troops marched out of Mexico City toward the Gulf Coast. On August 1, 1848, the last U.S. soldiers in Mexico boarded transports at Veracruz for the journey home.

Legacies of Conquest

California's military governor, Colonel R. B. Mason, invited a recent graduate of West Point, Lieutenant William T. Sherman, into his office in Monterey. He gestured to a pair of dull yellow rocks, which rested atop a pile of papers on his desk. Lifting one of the curious objects, Sherman asked: “Is it gold?” The two officers headed for the diggings around Sutter's Fort and reported their findings to Washington D.C. They announced that “there is more gold in the country drained by the Sacramento and San Joaquin Rivers than will pay the cost of the present war with Mexico a hundred times over.”

Thus began the gold rush of 1849. Upon hearing the incredible news, soldiers deserted their posts and raced into northern California. Likewise, sailors with “gold fever” abandoned their ships. Thousands of Americans journeyed westward to strike it rich, while miners from China, Hawaii, Peru, Chile, and Mexico flocked to the Pacific Coast. Prospectors along the rivers found $30,000 to $50,000 worth of gold each day. The Mexican cession not only extended the boundaries of the U.S. but also inflated the ambitions of the newcomers.

While Americans appraised the Mexican cession, a few military leaders turned their attention to electoral politics. Nominated by the Whigs, Taylor won the presidential election of 1848 on a platform of “Peace, Prosperity, and Union.” Because he died of acute gastroenteritis two years later, the Whigs tapped Scott as their next nominee.

Figure 6.3 Nathaniel Currier, An Available Candidate, 1848. Prints and Photographs Division, Library of Congress


Scott lost the contest in 1852 to a former officer under his command, Pierce. Though dubbed “Young Hickory of the Granite Hills” by the Democrats, Pierce's rivals noted his excessive drinking and unremarkable military record. They mocked him with the derisive line: “The Hero of Many a Well Fought Bottle.” Partisan platforms focused upon domestic concerns, because neither Taylor nor Pierce confronted external threats to national security.

In the absence of external threats, Americans looked for opportunities to promote the Monroe Doctrine. Even if the Clayton–Bulwer Treaty of 1850 disavowed military efforts to occupy the Isthmus of Panama, the U.S. appeared more aggressive within the western hemisphere. The American ambassador to Spain, Pierre Soulé, gained British and French approval of the Ostend Manifesto, which called upon the U.S. to contemplate seizing the island of Cuba. Quitman, the first president of the Aztec Club, recruited several thousand volunteers for a filibustering expedition, but he eventually aborted plans to “excite revolutionary movements” on the Spanish-held island. The Pierce administration recognized the illegitimate regime of William Walker, an American soldier of fortune who briefly took control of Baja California and Nicaragua. Given the impressive display of military prowess against Mexico, the U.S. touted the prospects of dominion from the Caribbean Sea to South America.

U.S. dominion on the Pacific Coast depended upon the construction of a transcontinental system of railroads, which prompted the War Department to authorize a new round of topographical surveys. Pierce instructed James Gadsden, the new minister to Mexico, to negotiate a treaty that secured enough territory south of the Gila River for a transit route from Texas to California. He found that Santa Anna, who had resumed power in Mexico City, needed money to stabilize his restored regime. While abrogating the Treaty of Guadalupe Hidalgo, the Gadsden Purchase Treaty in 1854 acquired 45,535 square miles of Mexican desert in exchange for a payment of $10 million.

The difficulty of supplying military outposts across the American deserts led to an experiment with exotic pack animals in 1855. As directed by Secretary of War Jefferson Davis, the Army purchased 75 camels from North Africa and sent them to Texas. They carried heavy loads, walked difficult terrain, and consumed little water. However, their appearance on the trails stampeded horses, mules, and cattle. Once Army officers began complaining to the War Department, the camel experiment ended.

The most important innovation by the War Department involved combat arms. National armories at Springfield, Massachusetts, and Harpers Ferry, Virginia, began manufacturing a new type of muzzle-loading rifle, which spun a Minié ball through a grooved barrel to achieve an effective range of 400 to 600 yards. With proper training, U.S. soldiers achieved a rate of fire measured at three rounds per minute. Furthermore, the introduction of rifling into field and coastal artillery pieces enhanced the accuracy and range of U.S. batteries. The Army organized its first cavalry regiments by 1855, which increased the total number of combat regiments in federal service to 19. Consequently, the next generation of West Point cadets came to terms with the tactical implications of massive firepower.

Meanwhile, the Navy rode a wave of maritime enthusiasm to become the fifth-largest force in the world. As the age of steam began to eclipse the age of sail, the Navy Department authorized more expeditions that went beyond the continental U.S. While venturing abroad, naval professionals delicately balanced economic, scientific, diplomatic, and military objectives. Crews explored the Amazon River, the Brazilian coast, the Rio de la Plata, the Rio Paraguay, the Bering Strait, and the China Sea. In retaliation for an attack on U.S. citizens residing in Nicaragua, the sloop-of-warCyane bombarded the port of San Juan del Norte during 1854. Surveying rivers inside South America a year later, the U.S.S. Water Witch, a steam-powered gunboat, was attacked by Paraguayans. Afterward, a naval expedition returned to Paraguay and obtained a formal apology along with a commercial treaty from the government.

Another naval expedition during the 1850s involved Commodore Perry, who steamed toward Asia to demonstrate “our pacific intentions.” Called the “Father of the Steam Navy,” he took charge of the effort to open Japan to the U.S. His dark-hulled sidewheel steamer, the U.S.S. Mississippi, served as the flagship for a small squadron that entered Tokyo Bay. After consulting with the Secretary of the Navy, John P. Kennedy, he threatened to use force if the Tokugawa Shogunate denied him permission to come ashore. Using a combination of persuasion and imposition, his parlays produced the Treaty of Kanagawa on March 31, 1854. He returned to the U.S. a hero, which prompted Congress to vote him a $20,000 bonus.

The U.S. possessed deep-water ports on the East and West Coasts, while exports flowed in all directions. Rich with revenue streams, the federal government enjoyed a treasury surplus that amounted to millions of dollars. However, a designing generation grew less willing to compromise in regard to the expansion of slavery across the North American continent. Though Americans expected the dismemberment of Mexico to enhance national security, few anticipated the internal conflicts within their own country that erupted as a legacy of conquest.


The armed forces of the U.S. transformed the nation into a colossus that sprawled across lands claimed in previous centuries by the European powers. With American troops moving into Texas and Oregon in 1846, they set off a boundary dispute with Mexico. They repulsed Mexican regiments along the Rio Grande and took the initiative in decisive battles. After Congress declared war on the Mexican government, naval actions secured key ports on the Pacific Coast of North America. The New Mexico and California provinces fell quickly to lightning strikes on the periphery, while Santa Anna resolved to defend the centers of power around Mexico. The intense fighting culminated with the occupation of Mexico City, which produced the Treaty of Guadalupe Hidalgo in 1848. In the wake of the Mexican War, the Monroe Doctrine broadly defined the operational theaters of the American military within the western hemisphere.

The Mexican War represented the first time in history that the American military conquered a foreign country. U.S. operations against Santa Anna's defenses appeared both innovative and bold, especially during the amphibious assault at Veracruz. Nevertheless, the successful campaigns resonated with the conventional doctrines of Napoleonic warfare. Despite the terrible price associated with combat, the armies in the field typically approached their enemies with restraint and civility. In fact, Scott's strategy to “conquer a peace” revealed his study of Francis Patrick Napier's three-volume History of the War in the Peninsula (1835). Grasping more than mere tactics, U.S. commanders possessed an extraordinary degree of physical and moral courage. Soldiers and sailors demonstrated a level of competence that greatly surpassed that of their predecessors in uniform. Ultimately, the display of the Stars and Stripes over the Palace of the Montezumas signaled U.S. dominance in the Americas for years to come.

Though acknowledging the power of the U.S., the people of Mexico bitterly remembered the war between the two nations. As a central event of their own national history, generations resented the fact that the “damned Yankees” invaded their homeland. Moreover, the Treaty of Guadalupe Hidalgo allowed the invaders to absorb approximately one-third of Mexico's land base. Areas linked together for centuries were broken apart, which rendered Hispanic and Indian communities within the American West more vulnerable to the abuses of outsiders. The state-sponsored violence imparted greater stridency to the concept of race, which cast a pall over relations along the border for decades. “Poor Mexico,” an old Mexican proverb lamented, “so far from God and so close to the United States.”

For most Americans, however, the conquest of Mexico marked the high tide of Manifest Destiny. As the U.S. population surged to 22 million during wartime, well over 60,000 volunteered for military service. Wearing the uniform had never seemed more romantic, even if some congressmen in Washington D.C. criticized the war effort. Designed in the 1850s, the Statue of Freedom atop the dome of the Capitol included a military helmet as well as a sword and a shield. While their anthem noted “the Halls of Montezuma,” the Marine Corps added a red stripe to their dress-uniform trousers to commemorate the storming of Chapultepec. The distant battlefields constituted a training ground for scores of West Point graduates, who came of age while marching on foreign soil. American warriors fondly recalled the education of their senses in Mexico, but the acquisition of new lands intensified the sectional discord that eventually plunged them into a civil war.

Essential Questions

1 What did the American military accomplish in the Mexican War?

2 Which U.S. commanders showed exemplary leadership? Which ones did not?

3 Why were the American people divided by the war and its consequences?

Suggested Readings

Bauer, Jack. The Mexican War, 1846–1848. Annapolis, MD: Naval Institute Press, 1974.

Bauer, Jack. Zachary Taylor: Soldier, Planter, Statesman of the Old Southwest. Baton Rouge: Louisiana State University Press, 1985.

Clayton, Lawrence R., and Joseph E. Chance, eds. The March to Monterrey: The Diary of Lieutenant Rankin Dilworth, U.S. Army. El Paso: Texas Western Press, 1996.

DeLay, Brian. War of a Thousand Deserts: Indian Raids and the U.S.–Mexican War. New Haven: Yale University Press, 2008.

Dugard, Martin. The Training Ground: Grant, Lee, Sherman, and Davis in the Mexican War, 1846–1848. New York: Little, Brown, 2008.

Eisenhower, John S. D. So Far From God: The U.S. War with Mexico, 1846–1848. New York: Random House, 1989.

Foos, Paul. “A Short, Offhand, Killing Affair”: Soldiers and Social Conflict during the Mexican–American War. Chapel Hill: University of North Carolina Press, 2002.

Greenberg, Amy S. Manifest Manhood and the Antebellum American Empire. Cambridge: Cambridge University Press, 2005.

Heidler, David S., and Jeanne T. Heidler. The Mexican War. Westport, CT: Greenwood Press, 2006.

Henderson, Timothy J. A Glorious Defeat: Mexico and its War with the United States. New York: Hill & Wang, 2007.

Hietala, Thomas. Manifest Design: American Exceptionalism and Empire. Revised edition. Ithaca, NY: Cornell University Press, 2003.

Johannsen, Robert Walter. To the Halls of the Montezumas: The Mexican War in the American Imagination. New York: Oxford University Press, 1985.

Johnson, Timothy D. Winfield Scott: The Quest for Military Glory. Lawrence: University Press of Kansas, 1998.

McCaffrey, James M. Army of Manifest Destiny: The American Soldier in the Mexican War, 1846–1848. New York: New York University Press, 1992.

Pinheiro, John C. Manifest Ambition: James K. Polk and Civil–Military Relations During the Mexican War. Westport, CT: Greenwood Press, 2007.

Wilentz, Sean. The Rise of American Democracy: Jefferson to Lincoln. New York: W. W. Norton, 2005.

Wiley, Peter Booth. Yankees in the Land of the Gods: Commodore Perry and the Opening of Japan. New York: Penguin, 1990.

Winders, Richard Bruce. Mr. Polk's Army: The American Military Experience in the Mexican War. College Station: Texas A&M University Press, 1997.

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