Everyone has been warned that sometimes what is popular is not always right. America’s history clearly bears this out. There are so many examples of things – slavery, Jackson’s Native American policy, war with Mexico – that were popular in their own time but are seen by us today as clearly morally wrong.

That brings us to our question: How can individuals stand up for what they know is right, even when it’s popular? Whether in school, in politics, at work or with friends, everyone will eventually be faced with this choice. In 1846, the United States went to war with Mexico. The United States clearly instigated the fight, and the objective was clearly to gain control of the land that is now New Mexico, Arizona, Nevada and California. Most Americans supported the decision to go to war and thousands of patriotic, brave young men volunteered to join the army.

A small group of equally brave Americans decided to stand up to the majority and argue against the war. We see them today as being on the right side of history, but they were in the minority at the time – unpopularly criticizing their government as their neighbors risked their lives for the glory of their country. It is hard to imagine anyone describing them as brave at the time.

So what do you do when you believe you are right, adrift in a sea of your friends, coworkers, neighbors, and compatriots who all think you are wrong?


Since the conquest of Cortez, Mexico had been Spanish territory, and at the start of the 1800s, the Spanish government began actively encouraging Americans to settle Texas, their northernmost province. The few Mexican farmers and ranchers who lived there were under constant threat of attack by hostile Native American tribes, especially the Comanche, who supplemented their hunting with raids in pursuit of horses and cattle.

To increase the non-Native population in Texas and provide a buffer zone between its hostile tribes and the rest of Mexico, Spain began to recruit empresarios who brought settlers to the region in exchange for generous grants of land. Moses Austin, a once-prosperous entrepreneur reduced to poverty by the Financial Panic of 1819, requested permission to settle three hundred English-speaking American residents in Texas. Spain agreed on the condition that the resettled people convert to Roman Catholicism.

Austin died in 1821 before being able to carry out his dream, but asked his son Stephen to continue his plans, and Mexico, which had won independence from Spain the same year, allowed Stephen to take control of his father’s grant. Like Spain, the new Mexican government also encouraged settlement in the state of Coahuila y Texas and passed colonization laws to encourage immigration. Thousands of Americans, primarily from neighboring American slave states, flocked to Texas and quickly outnumbered the Tejanos, the Mexican residents of the region. The soil and climate were good for cotton production and Texas offered a good opportunity to expand slavery. Land was plentiful and offered at generous terms. Unlike the American government, Mexico allowed buyers to pay for their land in installments and did not require a minimum purchase. Furthermore, to many Whites, it seemed not only their God-given right but also their patriotic duty to populate the lands beyond the Mississippi River, bringing with them American slavery, culture, laws, and political traditions.


Most Americans who migrated to Texas at the invitation of the Mexican government did not shed their identity as Americans or loyalty to the United States. For instance, the majority of these new settlers were Protestant, and though they were not required to attend the Catholic mass, Mexico’s prohibition on the public practice of other religions upset them and they routinely ignored it.

Accustomed to representative democracy, jury trials, and the defendant’s right to appear before a judge, the Anglo-American settlers in Texas also disliked the Mexican legal system, which provided for an initial hearing by an alcalde, an administrator who often combined the duties of mayor, judge, and law enforcement officer. The alcalde sent a written record of the proceeding to a judge in Saltillo, the state capital, who decided the outcome. Settlers also resented limited representation in the state legislature.

Their greatest source of discontent, however, was the Mexican government’s 1829 abolition of slavery. Most American settlers were from southern states, and many had brought slaves with them. Mexico tried to accommodate them by maintaining the fiction that the slaves were indentured servants. But American slaveholders in Texas distrusted the Mexican government and wanted Texas to be a new slave state.

The dislike of most for Roman Catholicism, the prevailing religion of Mexico, and a widely held belief in American racial superiority led them generally to regard Mexicans as dishonest, ignorant, and backward. Belief in their own superiority inspired some Texans to undermine the power of the Mexican government. When empresario Haden Edwards attempted to evict people who had settled his land grant before he gained title to it, the Mexican government nullified its agreement with him. Outraged, Edwards and a small party of men took prisoner the alcalde of Nacogdoches. The Mexican army marched to the town, and Edwards and his troop then declared the formation of the Republic of Fredonia between the Sabine and Rio Grande Rivers. To demonstrate loyalty to their adopted country, a force led by Stephen Austin hastened to Nacogdoches to support the Mexican army. Edwards’s revolt collapsed, and the revolutionaries fled Texas.

The growing presence of American settlers in Texas, their reluctance to abide by Mexican law, and their desire for independence caused the Mexican government to grow wary. In 1830, it forbade future immigration and increased its military presence in Texas. Settlers continued to stream illegally across the long border and by 1835, there were 20,000 Americans in Texas.

Fifty-five delegates from the Anglo-American settlements gathered in 1831 to demand the suspension of customs duties, the resumption of immigration from the United States, better protection from Native American tribes, the granting of promised land titles, and the creation of an independent state of Texas separate from Coahuila. Ordered to disband, the delegates reconvened in early April 1833 to write a constitution for an independent Texas. Surprisingly, General Antonio Lopez de Santa Anna, Mexico’s new president, agreed to all demands, except the call for statehood. Coahuila y Texas made provisions for jury trials, increased Texas’s representation in the state legislature, and removed restrictions on commerce.

Texans’ hopes for independence were quashed in 1834, however, when Santa Anna dismissed the Mexican Congress and abolished all state governments, including that of Coahuila y Texas. In January 1835, reneging on earlier promises, he dispatched troops to the town of Anahuac to collect customs duties. Lawyer and soldier William B. Travis and a small force marched on Anahuac in June, and the fort surrendered. On October 2, Anglo-American forces met Mexican troops at the town of Gonzales. The Mexican troops fled and the Americans moved on to take San Antonio.

Primary Source: Engraving

Antonio Lopez de Santa Anna, president of Mexico during both the Texas Revolution and then again during the Mexican-American War.

Now more cautious, delegates to the Consultation of 1835 at San Felipe de Austin voted against declaring independence, instead drafting a statement, which became known as the Declaration of Causes, promising continued loyalty if Mexico returned to a constitutional form of government. They selected Henry Smith, leader of the Independence Party, as governor of Texas and placed Sam Houston, a former soldier who had been a congressman and governor of Tennessee, in charge of its small military force.

The Consultation delegates met again in March 1836. They declared their independence from Mexico and drafted a constitution calling for an American-style judicial system and an elected president and legislature. Significantly, they also established that slavery would not be prohibited in Texas. Many wealthy Tejanos supported the push for independence, hoping for liberal governmental reforms and economic benefits.


Mexico had no intention of losing its northern province. Santa Anna and his army of 4,000 had besieged the Texan city of San Antonio in February 1836. Hopelessly outnumbered, its 200 defenders, under Travis, fought fiercely from their refuge in an old Catholic mission known as the Alamo. After ten days however, the mission was overrun and all but a few of the defenders were dead, including Travis and James Bowie, the famed frontiersman, land speculator and slave trader. A few male survivors, possibly including the frontier legend and former Tennessee congressman Davy Crockett, were led outside the walls and executed. The few women and children inside the mission were allowed to leave with the only adult male survivor, a slave owned by Travis who was then freed by the Mexican Army. Terrified, they fled. Although hungry for revenge, the Texas forces under Sam Houston nevertheless retreated across Texas, gathering recruits as they went.

Secondary Source: Painting

One artist’s impression of the last stand of the Texans at the Alamo. Davy Crockett stands tall as the hero of the battle.

Two months later, Houston and his army came upon Santa Anna’s encampment on the banks of San Jacinto River on April 21, 1836 and waited as the Mexican troops settled for an afternoon nap. Assured by Houston that “Victory is certain!” and told to “Trust in God and fear not!” the seven hundred men descended on a sleeping force nearly twice their number with cries of “Remember the Alamo!” Within fifteen minutes the Battle of San Jacinto was over. Approximately half the Mexican troops were killed, and the survivors, including Santa Anna, taken prisoner. The Texas Revolution was over.

Santa Anna grudgingly signed a peace treaty and was sent to Washington, where he met with President Andrew Jackson and, under pressure, agreed to recognize an independent Texas with the Rio Grande River as its southwestern border. By the time the agreement had been signed, however, Santa Anna had been removed from power in Mexico and the Mexican Congress refused to be bound by Santa Anna’s promises and continued to insist that the renegade territory still belonged to Mexico.

Primary Source: Photograph

Sam Houston, the George Washington of Texas who led Texas to independence and served as president of the Lone Star Republic before serving as governor and senator for the state after it joined the Union.


In September 1836, military hero Sam Houston was elected president of Texas, and, following the relentless logic of American expansion, Texans voted in favor of annexation to the United States. This had been the dream of many settlers in Texas all along. They wanted to expand the United States west and saw Texas as the next logical step. Slaveholders there, such as Sam Houston, William B. Travis and James Bowie, believed too in the destiny of slavery. Mindful of the vicious debates over Missouri that had led to talk of disunion and war, American politicians were reluctant to annex Texas or, indeed, even to recognize it as a sovereign nation. Annexation would almost certainly mean war with Mexico, and the admission of a state with a large slave population would bring the issue of slavery once again to the fore. Texas had no choice but to organize itself as the independent Lone Star Republic. To protect itself from Mexican attempts to reclaim it, Texas sought and received recognition from France, Great Britain, Belgium, and the Netherlands. The United States did not officially recognize Texas as an independent nation until March 1837, nearly a year after the final victory over the Mexican army at San Jacinto.

Uncertainty about its future did not discourage Americans committed to expansion, especially slaveholders, from rushing to settle in the Lone Star Republic, however. Between 1836 and 1846, its population almost tripled. By 1840, nearly 12,000 enslaved Africans had been brought to Texas by American slaveholders. Many new settlers had suffered financial losses in the severe financial depression of 1837 and hoped for a new start in Texas. According to folklore, across the United States, homes and farms were deserted overnight, and curious neighbors found notes reading only GTT – Gone to Texas. Many European immigrants, especially Germans, also settled in Texas during this period.

Americans in Texas generally treated both Tejano residents and Native Americans with utter contempt, eager to displace and dispossess them. Failing to return the support Tejano neighbors had extended during the rebellion, Americans instead repaid them by seizing their lands. In 1839, the republic’s militia attempted to drive out the Cherokee and Comanche. The impulse to expand did not lay dormant, and White settlers and leaders soon cast their gaze on the Mexican province of New Mexico as well. Repeating proven tactics, a Texas force set out in 1841 intent on taking Santa Fe. Its members encountered an army of New Mexicans and were taken prisoner and sent to Mexico City. On Christmas Day, 1842, Texans avenged a Mexican assault on San Antonio by attacking the Mexican town of Mier. In August, another Texas army was sent to attack Santa Fe, but Mexican troops forced them to retreat. Clearly, hostilities between Texas and Mexico had not ended simply because the Texans had won at San Jacinto.


A fervent belief in expansion gripped the United States in the 1840s. In 1845, a New York newspaper editor, John O’Sullivan, introduced the concept of manifest destiny to describe the very popular idea of the special role of the United States in overspreading the continent: the divine right and duty of White Americans to seize and settle the American West, thus spreading Protestant, democratic values.

In this climate of opinion, voters in 1844 elected James K. Polk, a slaveholder from Tennessee, because he vowed to annex Texas as a new slave state and take Oregon. Annexing Oregon was an important objective for the United States because it appeared to be an area rich in commercial possibilities. Northerners favored control of Oregon because ports in the Pacific Northwest would be gateways for trade with Asia. Southerners hoped that, in exchange for their support of expansion into the Northwest, Northerners would not oppose plans for expansion into the Southwest.

Secondary Source: Map

The disputed Oregon Territory.

President Polk, whose campaign slogan in 1844 had been “Fifty-four forty or fight!” asserted the United States’ right to gain full control of what was known as Oregon Country, from its southern border at 42° latitude, the current boundary with California, to its northern border at 54° 40’ latitude. According to an 1818 agreement, Great Britain and the United States held joint ownership of this territory, but the 1827 Treaty of Joint Occupation opened the land to settlement by both countries. Realizing that the British were not willing to cede all claims to the territory, Polk proposed the land be divided at 49° latitude, the current border between Washington and Canada. The British, however, denied American claims to land north of the Columbia River, Oregon’s current northern border. Indeed, the British foreign secretary refused even to relay Polk’s proposal to London. However, reports of the difficulty Great Britain would face defending Oregon in the event of an American attack, combined with concerns over affairs at home and elsewhere in its empire, changed the minds of the British, and in June 1846, Queen Victoria’s government agreed to a division at the 49th Parallel.

Although he had been elected while blustering about war with Britain over Oregon, Polk ultimately favored a diplomatic solution. When it came to Mexico, however, Polk and the American people proved willing to use force to wrest more land for the United States. In keeping with voters’ expectations, President Polk set his sights on the Mexican state of California.

Tensions between the United States and Mexico rapidly deteriorated in the 1840s as American expansionists eagerly eyed Mexican land to the west, including the lush northern Mexican province of California. Indeed, in 1842, an American naval fleet, incorrectly believing war had broken out, seized Monterey, California, a part of Mexico. Monterey was returned the next day, but the episode only added to the uneasiness with which Mexico viewed its northern neighbor.

After the mistaken capture of Monterey, negotiations about purchasing the port of San Francisco from Mexico broke off until September 1845. Then, following a revolt in California that left it divided in two, Polk attempted to purchase Upper California and New Mexico as well. These efforts went nowhere. The Mexican government, angered by American actions, refused to recognize the independence of Texas.

Finally, after nearly a decade of public clamoring for the annexation of Texas, in December 1845 Polk officially agreed to the annexation of the former Mexican state, making the Lone Star Republic an additional slave state. Incensed that the United States had annexed Texas, however, the Mexican government refused to discuss the matter of selling land. Indeed, Mexico refused even to acknowledge Polk’s emissary, John Slidell, who had been sent to Mexico City to negotiate. Not to be deterred, Polk encouraged Thomas O. Larkin, the American consul in Monterey, to assist any American settlers and any Californios, the Mexican residents of the state, who wished to proclaim their independence from Mexico. By the end of 1845, having broken diplomatic ties with the United States over Texas and having grown alarmed by American actions in California, the Mexican government warily anticipated the next move. It did not have long to wait.


The United States had long argued that the Rio Grande was the border between Mexico and the United States, and at the end of the Texas Revolution, Santa Anna had been pressured to agree. Mexico’s new government, however, refused to be bound by Santa Anna’s promises and insisted the border lay farther north, at the Nueces River. To set it at the Rio Grande would, in effect, allow the United States to control land it had never occupied. In Mexico’s eyes, therefore, President Polk had violated sovereign Mexican territory when he ordered American troops into the disputed lands in 1846. From the Mexican perspective, the United States had invaded their nation.

In January 1846, the American force that was ordered to the banks of the Rio Grande to build a fort on the “American” side encountered a Mexican cavalry unit on patrol. Shots rang out, and 16 American soldiers were killed or wounded. Angrily declaring that Mexico had “invaded our territory and shed American blood upon American soil,” President Polk demanded the United States declare war on Mexico. On May 12, Congress obliged. The ensuing conflict is known on the northern side of the Rio Grande as the Mexican-American War, and on the southern side as the American Intervention in Mexico.

A small but vocal anti-slavery faction decried the decision to go to war, arguing that Polk had deliberately provoked hostilities so the United States could annex more slave territory. Illinois representative Abraham Lincoln and other members of Congress issued the Spot Resolutions in which they demanded to know the precise spot on American soil where American blood had been spilled. Many Whigs also denounced the war.

Democrats, however, supported Polk’s decision, and volunteers for the army came forward in droves from every part of the country except New England, the seat of anti-slavery sentiment. Enthusiasm for the war was aided by the widely held belief that Mexico was a weak, impoverished country and that the Mexican people, perceived as ignorant, lazy, and controlled by a corrupt Roman Catholic clergy, would be easy to defeat.

American military strategy had three main objectives. First, take control of northern Mexico including New Mexico. Second, seize California, and third, capture Mexico City. General Zachary Taylor and his Army of the Center were assigned to accomplish the first goal, and with superior weapons they soon captured the city of Monterrey. Taylor became a hero in the eyes of the American public, and Polk appointed him commander of all American forces. General Stephen Watts Kearny, commander of the Army of the West, accepted the surrender of Santa Fe, New Mexico, and moved on to take control of California. Despite Kearny’s assurances that New Mexicans need not fear for their lives or their property, the region’s residents rose in revolt in January 1847 in an effort to drive the Americans away.

Kearny, meanwhile, arrived in California to find it already in American hands through the joint efforts of California settlers, American naval commander John Sloat, and John C. Fremont, a former army captain and son-in-law of Missouri senator Thomas Benton. Sloat seized the town of Monterey in July 1846, less than a month after a group of American settlers led by William B. Ide had taken control of Sonoma and declared California a republic. This Bear Flag Republic was short-lived. A week after the fall of Monterey, the navy took San Francisco with no resistance and California fell under American control. Although some Californios staged a short-lived rebellion in September 1846, many others submitted to the American takeover. Thus Kearny had little to do other than take command of California as its governor.

Leading the Army of the South was General Winfield Scott. Both Taylor and Scott were potential competitors for the presidency, and correctly anticipating that whoever seized Mexico City would become a hero, Polk assigned Scott the campaign to avoid elevating the more popular Taylor.

Scott captured Veracruz in March 1847 and slowly closed in on the capital. His march almost exactly mirrored the route taken by Spanish conquistador Hernán Cortés in 1519. Every step of the way was difficult however, as Mexican soldiers and civilians both fought bravely to save their land from the invaders. Mexico City’s defenders, including young cadets at the Castle of Chapultepec, Mexico’s premier military academy, fought to the end. According to legend, cadet Juan Escutia’s last act was to save the Mexican flag, and he leapt from the city’s walls with it wrapped around his body. All efforts to stop the Americans were in vain, however, and on September 14, 1847, Scott marched triumphantly into Mexico City’s central plaza.

Secondary Source: Painting

The Battle of Chapultepec, the Mexican military academy where teenage cadets defended their school against the overwhelming American army.

The Treaty of Guadalupe Hidalgo, officially ending the war, was signed in February 1848, and was a triumph for American expansionism. Under the terms of the treaty, Mexico ceded nearly half its land to the United States. The Mexican Cession, as the conquest of land west of the Rio Grande was called, included the current states of California, New Mexico, Arizona, Nevada, Utah, and portions of Colorado and Wyoming. Mexico also recognized the Rio Grande as the border with the United States. Mexican citizens in the ceded territory were promised American citizenship in the future when the territories they were living in became states. In exchange, the United States agreed to assume $3.35 million worth of Mexican debts owed to American citizens, paid Mexico $15 million for the loss of its land, and promised to guard the residents of the Mexican Cession from Native American raids.

Like the outbreak of the war itself, the Treaty of Guadalupe Hidalgo was well received back home, but still had its critics. Some argued the United States should have taken all of Mexico. Many of these were Southerners who desired the annexation of more slave territory. Many of the treaty’s critics were also Southerners who did not want to incorporate Mexico’s large mestizo population into the United States. Others, especially Northerners who were still whipped up with Second Great Awakening and anti-Irish immigrant fervor, did not want to absorb a nation of Roman Catholics.


Many of the military leaders who fought on both sides of the Civil War some twenty years later fought as junior officers in Mexico. This list includes Ulysses S. Grant, George B. McClellan, William T. Sherman, George Meade, and Ambrose Burnside as well as Southerners Robert E. Lee, Stonewall Jackson and the future Confederate President Jefferson Davis.

From the perspective of 21st Century historians, the rationale for the war is clearly unjust. Even at that time, there were some who understood that Polk’s explanations were an excuse to wrest land from Mexico. President Ulysses S. Grant, who had been a young army lieutenant under General Taylor, recalled in 1885 that, “Generally, the officers of the army were indifferent whether the annexation was consummated or not; but not so all of them. For myself, I was bitterly opposed to the measure, and to this day regard the war, which resulted, as one of the most unjust ever waged by a stronger against a weaker nation. It was an instance of a republic following the bad example of European monarchies, in not considering justice in their desire to acquire additional territory.” Grant also expressed the view that the war against Mexico had brought punishment on the United States in the form of the American Civil War. “The Southern rebellion was largely the outgrowth of the Mexican war. Nations, like individuals, are punished for their transgressions. We got our punishment in the most sanguinary and expensive war of modern times.” This view was shared by the Transcendentalist Ralph Waldo Emerson, who towards the end of the war wrote, “The United States will conquer Mexico, but it will be as the man swallows the arsenic, which brings him down in turn. Mexico will poison us.”

Nevertheless, the war was a decisive event for the nation, marking a significant waypoint in its growth as a military power, and a milestone in the narrative of Manifest Destiny.

The war also elevated the status of General Zachary Taylor, who Polk had accurately predicted would become a national hero. Despite a general lack of political experience, the Whig Party recruited Taylor to run for president and he won in 1848. As president, Taylor sought to reduce growing tensions about the expansion of slavery into the territories he had help win, but died of a digestive illness after only 16 months in office.


The conclusion of the Mexican-American War set off a bid to build railroads across the new territory to California. One of the routes proposed by the Southern Pacific Railroad, however, would need to travel north of the Gila River through territory that would not be amenable to railroad construction. The company officials knew that a route south of the river would be less expensive and easier to build because the land was flatter.

That territory was still Mexican, so in 1853, President Franklin Pierce sent James Gadsden to Mexico to negotiate a redefinition of the border. The Mexican government was desperately short of cash and agreed to the American offer to purchase the land for $10 million. The new territory of 30,000 square miles is now the southern edges of New Mexico and Arizona. The Gadsden Purchase was the final puzzle piece that make up what is now the 48 contiguous United States.

Secondary Source: Map

All the various territorial acquisitions that formed the final lower 48 states.


Emerson’s study must have been a lonely place during the Mexican-American War. There with just a few other critics of the war, the Transcendentalist philosopher wrote his criticism and watched the waves of history sweep past.

It turns out, of course, that Emerson and the few others who objected to America’s war of conquest against Mexico were absolutely right. As General Grant noted, the country was punished by fate, or in Emerson’s eloquent metaphor, poisoned. This must have been little consolation for those who were strong enough of conviction to stand up and speak out against what they knew was morally wrong when the nation was quite literally marching in the opposite direction.

What could they have done differently? What would you have done? What can you do now when faced with such a situation? When something is wrong but popular, what can you do to resist?



BIG IDEA: Americans who moved to Texas initiated a war for independence from Mexico, and later President Polk launched a war against Mexico that resulted in Mexico giving half of its land to the United States.

Texas was originally part of New Spain, and then Mexico after Mexico won independence. Mexico invited American settlers to move into Texas to increase the non-Native population. These were Tejanos, and they brought their slaves with them. When Mexico outlawed slavery, the Tejanos decided to fight for independence from Mexico. They did not want to give up slavery, they did not speak Spanish, and they were not Catholic.

The Texas Revolution was a success for the Tejanos. After the loss of the Alamo, they defeated Mexican dictator Santa Anna and forced him to recognize Texan independence. Sam Houston became the president of the new Republic of Texas. Almost immediately they asked Congress to annex the territory, but because of concerns about balancing slave and free states in the Senate, Texas remained independent for ten years.

Americans started to believe in the idea of manifest destiny. They thought that God wanted their nation to stretch from the Atlantic to the Pacific Oceans. They elected James K. Polk president in 1844. He was a strong believer in this idea and promised to annex Texas. He also promised to go to war with Great Britain over control of the Oregon Territory.

Polk did go to war with Mexico, but chose to settle with Great Britain peacefully. The Oregon Territory was divided. The modern states of Oregon and Washington became American territory. British Columbia is now part of Canada.

Polk annexed Texas and then instigated a war with Mexico by sending American troops across the Nueces River into land both the United States and Mexico claimed. Some Americans believed a war with Mexico was wrong, but many others wanted land in the West and supported the effort. The war went well. American troops invaded Mexico, defeated Santa Anna and forced him to give up the Mexican Cession, which makes up most or all of what is now the states of Arizona, California, New Mexico, Nevada and Utah.

The Mexican-American War had some important impacts. Zachary Taylor who was the hero of the Mexican-American War was elected president. The young officers in the war later led the armies of the Civil War. Debate about expanding slavery into the new lands won from Mexico helped cause the Civil War.

The final piece of land that makes up the map of the United States we know today was the Gadsden Purchase. It was bought from Mexico in order to build a railroad along flat land between Texas and California.



Tejanos: Mexican-born Hispanic residents of Texas. They were outnumbered by the influx of American-born Whites in the early 1800s.

Antonio Lopez de Santa Anna: Mexican dictator who fought against the Texans in the Texas War for Independence. He was the Mexican commander at the Battles of the Alamo and San Jacinto. Later he led Mexico against the Americans in the Mexican-American War.

Sam Houston: Former governor of Tennessee who moved to Texas and led the Texas Revolution, was the president of the Republic of Texas and first Governor of the state once Texas joined the Union. A major city was named in his honor.

Davy Crockett: American outdoorsman, congressmen and frontier legend from Tennessee who died at the Alamo.

James K. Polk: President elected in 1844 who championed westward expansion. He annexed Texas, led the Mexican-American War and negotiated the resolution to the boundary dispute with the United Kingdom over the Pacific Northwest.

Californios: Mexican residents of California. Like the Tejanos, they lost many of their rights and land after California became part of the United States.

Zachary Taylor: American general who led an invasion of Mexico during the Mexican-American War. He was known as “Old Rough and Ready” and his exploits led to political popularity and eventually to his election to the presidency.

John C. Fremont: Explorer, army general, senator from California, wealthy gold miner, and surveyor of the route of the transcontinental railroad. He was a public hero and was the first nominee for president from the Republican Party, although he did not win.

Mestizo: An ethnic blend of Spanish and Native American. Most Mexicans and residents of the Mexican Cession who became residents of the United States were of this ethnic group.


Manifest Destiny: Belief held by many Americans, especially in the 1800s that it was clear that the nation would spread from the Atlantic to the Pacific Ocean. This belief fueled expansion, including migration of pioneers, war with Mexico and Native Americans, and a belief in the superiority of White, Christian culture.

Fifty-four forty or fight: President Polk’s rallying cry during the election of 1844. It referred to the northern boundary of the Oregon Territory. Eventually he abandoned this demand and settled to split the territory peacefully at a line further south.


Texas: Largest of the lower 48 states. It was a territory of Mexico before American-born Tejanos fought for independence in 1835. It was known as the Lone Star Republic for a decade before it was annexed by the United States in 1845.

The Alamo: Mission in San Antonio, Texas that was defended by Texans in 1836 against the Mexican Army under the command of Santa Anna at the start of the Texas Revolution. The Texans and their American allies were defeated, but they were remembered as martyrs and the loss became a source of inspiration for Texans.

Lone Star Republic: Nickname for the independent nation of Texas between 1836 and 1846.

Oregon Territory: Region that today includes the states of Oregon, Washington and the Canadian province of British Columbia. It was divided between the United States and Canada along 49th Parallel.

Pacific Northwest: Region that includes that states of Washington and Oregon.

American Southwest: Region that includes the states of New Mexico, Arizona, and sometimes expanded to include California, Nevada, Utah, Texas and Oklahoma.

Rio Grande: River the divides that United States and Mexico. It flows into the Gulf of Mexico and forms most of the southern border of Texas.

Nueces River: River just north of the Rio Grande that Mexico claimed was the boundary between the United States and Mexico. The dispute was used by President Polk to instigate the Mexican-American War.

Chapultepec: Mexican military school in Mexico City. It was attacked by American forces during the Mexican-American War and the valiant defense mounted by the teenage student cadets is now legendary in Mexico.

Mexican Cession: The land sold to the United States by Mexico at the end of the Mexican-American War. It includes the states of California, Nevada, New Mexico, Arizona, Utah and portions of Colorado and Wyoming.

Gadsden Purchase: Small strip of land purchased from Mexico in 1853 in order to provide flat land for a railroad between Texas and California. It forms the southernmost portions of Arizona and New Mexico.


Battle of San Jacinto: Last battle of the Texas Revolution in 1836, in which the Texans under the command of Sam Houston defeated Santa Anna’s Mexican forces and forced him to recognize Texan independence.

Texas Revolution: War between American-born Texans and the Mexican government under the command of Santa Anna in 1835 and 1836 that resulted in independence for Texas. It was fought largely due to disagreements about culture, language, religion and especially slavery.

Mexican-American War: War between the United States and Mexico between 1846 and 1848. It was a major victory for the United States and the subsequent Treaty of Guadalupe Hidalgo resulted in the Mexican Cession, the land that became the modern states of New Mexico, Arizona, Nevada, California and part of Utah.


Spot Resolutions: A series of resolutions passed in Congress at the start of the Mexican-American War by Polk’s Whig opponents demanding to know exactly where Americans had been killed by Mexican forces. The debate centered on the dispute over which river formed the border.

Treaty of Guadalupe Hidalgo: Treaty signed in 1848 that formally ended the Mexican-American War. As part of the agreement, Mexico sold about half of its territory to the United States. This land, called the Mexican Cession, includes the states of California, Nevada, New Mexico, Arizona, Utah and portions of a few other states as well.

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