History 110
Whose Manifest Destiny?
The Conquest of Northern Mexico

Discussion Goals:
- To understand the economic, social, and political status of Mexico at the time of American immigration.
- To examine the causes that led up to
the Mexican American War and the way it contributed to the growth of the
U.S. at Mexico’s expense.
- To study the consequences of the Mexican American War.
- To learn how the Mexicans fared in
“Occupied Mexico” - that portion of Northwest Mexico that came under control
of the US after 1848.
Excerpt from a Mexican textbook on the annexation of Texas an the U.S. intervention in Mexico, as presented in the book, As Others See Us.
"Texas was annexed to the United Staes by the treaty of April 12, 1844, despite the protests of our [Mexican] government and even though the treaty was rejected by the American Congress. Thereupon the annexation of the territory was proposed in the House and approved on March 1, 1845, which forced our Minisster in Washington to withdraw. The Texans, backed by the American government, claimed that its boundaries extended to the Rio Bravo del Norte [Rio Grand], whereas in fact the true limits had never passed the Nueces River. From this [boundary dispute] a long controversy developed [during which negotiations were carried on] in bad faith by the Americans.

They ordered trooops to invade places within our territory, operating with the greatest treachery, and pretended that it was Mexico which had invaded their territory, making Mexico appear as the aggressor. What they were really seeking was to provoke a war, a war in which the southern states of the Union were greatly interested, in order to acquire new territories which they could convert into states dominated by the slavery interests. But since the majority of the people in the United States were not pro-slavery nor favorable of a war of conquest, President Polk tried to give a defensive character to his first military moves, foreseeing the opposition which he would otherwide encounter. Once he obtained a declaration of war, Polk made it appear that he wanted nothing more than peaceful possession of the annexed territory...
The Mexican War was a brilliant move astutely planned by the United States. The magnificent lands of Texas and California with their ports on both oceans, the gold deposits soon to be discovered in the latter state, and the increase in territory which made possible the growth of slave states compensated the United States many times over the costs in men and money of the unjust acquisition..."
Goal #1: To understand the economic, social, and political status of Mexico at the time of American immigration
Map of Mexico at the time of Mexican independence and the year that Stephen Austin's immigrant party came to Mexico in 1821 - a year in which Rodopho Acuna notes the new nation was "bankrupt, and it needed time to build an infrastructure to unify the new country."

Goal #2: To examine the causes that led up to
the Mexican American War and the way it contributed to the growth of the
U.S. at Mexico’s expense
Causes of
the Mexican American War
- U.S. government adopted an aggressive
foreign policy designed to force Mexico to sell Texas.
- North American immigration to Texas, eventually making Americans the dominant population.
- American refusal to submit to Mexican laws.
- Mexico adopted a new, centralized government, thus forcing the Mexican states to relinquish some of their power.
- Anglo-American settlers sought more autonomy of Texas.
- Americans established the Republic of Texas with the western boundary at the Nueces River.
- The U.S. government annexed Texas with the western bourndary at the Rio Grande River.
First Cause - The U.S. government adopted an aggressive
foreign policy designed to force Mexico to sell Texas.
- 1804 - Americans formally displayed their interest in Mexico during the presidency of Jefferson. Napoleon had not defined the exact boundaries of the Louisiana Purchase, so Jefferson initially claimed Texas had been part of the purchase.
But Spain refused to acknowledge this claim.
- 1819 - In the Adams-Onis Treaty of 1819, the US gave up official claims over Texas in return for Florida.
- 1827 - President John Quincy Adams tried to purchase Texas for a million dollars, but Mexico refuses the offer.
- 1830 - President Andrew Jackson tried to purchase Texas for 5 million dollars but again, Mexico refuses the offer.
American interest in Texas will really heat up after two things are accomplished:
- a significant number of Americans had moved into Texas territory - enough to stimulate a move for independence; and
- a president with deeply expansionist ambitions moves into the White House.
Second Cause - Americans began immigrating to the Mexican territory of Texas and quickly became the dominant population.
- In late 1821, Moses Austin -
an American - received a grant from the new Mexican government to establish a colony of 300 American families in Texas.
- Each family was entitled to 170 acres for agriculture and another 128 acres for stock raising - a total of 298 acres. The government asked 12-1/2 cents per acre, tax free.
- The grant stipulated that all settlers must be Catholics or willing to convert to Catholicism; that all public transactions must take place in Spanish; and that all immigrants had to relinquish their US citizenship and take an oath of loyalty to Mexico.
- By the 1822, 300 families had arrived under the leadership of Moses' son - Stephen Austin who is pictured to the right. (Moses died before being able to immigrate.)
- When the Americans began arriving, they were the minority among 3,000 Mexican ranchers who lived in Texas - one of the least populated areas of the country.
- Many other Americans felt that if Austin could get such a generous grant, they could too. The United States was still struggling with the aftermath of the Panic of 1819 and soaring land prices within the United States made the Mexican land policy seem very generous.
Thus, a substantial migration began.
- In 1823, partly because American migration increased so rapidly, the Mexican government forbid the sale or purchase of slaves, required that the children of slaves be freed when they reached fourteen, and required that any slave introduced into Mexico by purchase or trade would also be freed.
- By 1824, the colony's American population exceeded 2,000 with about 450 slaves. They had largely excluded themselves from the 3,000 Mexicans.
- By 1825, the Mexican government began to worry about the increasing number of American immigrants and asked for an investigation of how colonization was proceeding in Texas.
- In 1829, the investigation found:
- Most Anglo Americans refused to become Mexican citizens, had largely isolated themselves from Mexicans, and perhaps most troubling - that the immigrants were ignoring the slave reforms passed by the state.
- In response, the Mexican government officially outlawed all slavery in Mexico.
- To circumvent the law, many Anglo colonists converted their slaves into indentured servants for life. Others simply called their slaves indentured servants without legally changing their status.
. Slaveholders wishing to enter Mexico would force their slaves to sign contracts claiming that the slaves owed money and would work to pay the debt. The low wages the slave would receive made repayment impossible, and the debt would be inherited,
- Texas outlawed this tactic in1832 by prohibiting worker contracts from lasting more than ten years.
- By 1836, Americans had become the domiant population in Texas; there were 38,000 American settlers in Texas -
settlers who held title to several huge land grants - and they owned approximately 5,000 slaves.
There were about 7,000 Mexicans living in Texas.
Third Cause - American refusal to submit to Mexican laws
- Americans, as discussed above, disobeyed all Mexican laws in regard to slavery.
- Additionally, while Americans had promised to convert to Catholicism and sign an oath of allegiance to Mexico, most had refused to do either.
- Then, in 1830, when Mexico prohibited further American immigration into Mexican territory, Americans ignored the immigration law and continued to cross the border in defiance of the law.
Fourth Cause - Mexico adopted a new, centralized government, thus forcing the Mexican states to relinquish some of their power.
- In 1832, Santa Anna led a revolt against Mexican president Bustamante which resulted in a short civil war in which Santa Anna was victorious.
- On June 12, 1834, Santa Anna dissolved Congress and he immediately formed a new centralized government - a dictatorship backed by the military.
Several states openly rebelled against the changes - including Coahuila y Tejas which soon frmed its own government, the Republic of Texas.
- This led to the next causation for war - Anglo American settlers' began to seek more autonomy for Texas
Fifth Cause - Anglo American settlers' began to seek more autonomy for Texas.
- The Mexican government attempted to address some of the Texans' concerns, especially allowing more American immigrants to settle in Texas , giving Texas more representation in the state legislature, and authorizing English as a second language.
- But i n 1835, Santa Anna revoked the Constitution and began centralizing and consolidating his power. As protests spread across Texas, Mexican officials blamed the Anglo settlers for the discord, noting that they continued to live in isolation from Mexicans and had not become citizens.
- These events led to the sixth and most important cause of the Mexican American War - the American declaration of the Republic of Texas.
Sixth Cause - Americans established the Republic of Texas with the western boundary at the Nueces River.
- American colonists proclaimed a provisional
government - the Republic of Texas and declared independence from Mexico on March 2, 1836.
- The American colonists maintained that Mexico had invited them to move to the country and they were determined "to enjoy 'the republican institutions to which they were accustomed in their native land, the United States of America."
- A battled ensued - the battle of the Alamo -
and ended with the Battle of San Jacinto on April 21, 1836. At San Jacinto, Sam Houston had organized a counterattack and surprised Santa Anna’s forces at San Jacinto. A systematic slaughter ensued. After the battle, 2 Americans and 630 Mexicans were dead. Santa Anna was captured and promised to convince the Mexican government to recognize the Republic of Texas.
- Santa Anna did not keep his promise and the Mexican Congress refused to accept Texas independence.
- In October 1836, Sam Houston became president of the new Republic of Texas with a western boundary at the Nueces River.
Seventh Cause - The U.S. government annexed Texas with the western boundary at the Rio Grande River.
- In 1838, Sam Houston had invited the U.S. to annex Texas, but Congress declined. Why? Mexico refused to recognize Texas independence and the Whigs felt annexation would bring war with Mexico and did not want another slave state entering the Union.
- However, in 1845, just days before President Tyler (Whig) left office for his successor, James K. Polk (Democrat), convinced Congress to annex Texas with the southern border set along the Rio Grande. Texas was admitted to the union as a slave state.
- But admission had not been easy. The United States Congress passed - after much debate and only a simple majority - a Joint Resolution for Annexing Texas to the United States.
- In July 1845, a popularly-elected Constitutional Convention met in Austin to consider both this annexation proposal as well as a proposed peace treaty with Mexico which would end the state of war between the two nations, but only if Texas remained an independent country.
The Convention voted to accept the Resolution for Annexing Texas and it was submitted to and approved by a popular vote in October 1845.

- Although the formal transfer of government did not occur until February 19, 1846, Texas statehood dates from the 29th of December, 1845.
- Opposition to Texas' admission to the United States was particularly strong in the Northern United States. Mexico immediately cut off relations with U.S. and insisted that Texas’s southern boundary was the Nueces River, not the Rio Grande which was 130 miles to the south. President Polk responded by ordering American troops under General Zachary Taylor to the disputed territory - the border area between the Nueces and the Rio Grande Rivers.
- The U.S. government declared it had no choice
but to go to war with Mexico. Mexican forces crossed the Rio Grande
to attack the U.S. army and on May 11, 1846, the U.S. was at war with Mexico. Not all Americans, however, supported the war as the document from the Massachusetts state government issued in 1847 indicates (see below).
- The Treaty of Guadalupe Hidalgo, signed on February 1, 1848, ceded Texas with the Rio Grande boundary, and all territory between Texas and the Pacific - territory that later became the states of New Mexico, California, Nevada, Utah, and most of Arizona, Wyoming, and Colorado. In return, the U.S. paid Mexico $15 million. Americans gained over 1 million square miles - an area amounting to one-half of all Mexico.

Massachusetts Protests the Mexican American War, 1847
"Resolved, That the present war with Mexico has its primary origin in the unconstitutional annexation to the United States of the foreign state of Texas ...; that it was unconstitutionally commenced by the order of the President, to General Taylor, to take military possession of territory in dispute between the United States and Mexico, and in the occupation of Mexico; and that it is now wage ingloriously, - by a powerful nation against a weak neighbor - unnecessarily and without just cause, at the immense cost of treasure and life, for the dismemberment of Mexico, and for the conquest, of a portioin of her territory, from which slavery has already been excluded, with the triple object of extending slavery, of strengthening the "Slave Power," ob obtaining the control of the Free States, under the Constitution of the United States.
Resolved, That such a war of conquest, so hateful in its objects, so wanton, unjust, and unconstitutional in its origin an character, must be regarded as a war against freedom, against humanity, against injustice, against the Uniion, against the Constitution, and against the Free States; and that a regard for the true interests and the highest honor o the country, not less than the impulses of Christian duty, should arouse all good citizens to join in efforts to arrest this gigantic crime, by withholding supplies, or other voluntary contributions, for its further prosecution; by calling for the withdrawal of our army within the established limits of the United States; and in every just way aiding the country to retreat from the disgraceful position of agression which it now occupies toward a weak, distracted neighbor and sister republic."
Goal #3: To study the consequences of the
War
- More than 12,000 lives were lost.
- U.S. spent more than $100 million
dollars.
- The U.S. acquired a colony that was 1 million acres (55% of all Mexico) and contained rich farmlands and natural resources
such as gold, silver, zinc, copper, oil, and uranium, as well as new ports
that would facilitate economic expansion across the Pacific.
- Disagreements over slavery escalated across the United States. A growing number of northerners were convinced that the War was started by southern slave owners who wanted to open the newly acquired lands to slavery.
- American political parties were weakened and subsequently, it became increasingly difficult for the nation's leaders to prevent slavery and the expansion of slavery from dominating Congressional activity for the next 12 years. We can especially see this with the controvery that began in 1845 over the Wilmot Proviso.
- David Wilmot, a Congressman from Pennsylvania who introduced the bill as soon as war broke out with Mexico, hoped to exclude slavery from any lands taken from Mexico. The provision passed the House but failed in the Senate. Although it was reintroduced several times over the next four years, it was always defeated. With each vote, party loyalty broke down, giving way to sectional divisions within the parties.
- Northern Democrats consistently favored the Proviso.
- Southern Democrats consistently opposed it.
- The Whigs were divided:
- Southern Whigs and northern "Cotton Whigs" dependent on cotton raw materials from th4 south, supported the Proviso;
- the "Conscience Whigs" opposed the expansion of slavery; and
- another group of Whigs formed a new party - the Free Soilers - and bolted from the party when Zachary Taylor, a southern slave owner and hero of the Mexican American War, was nominated in 1848 as the Whig candidate for President.
- It was one of the most unpopular wars in U.S. History. Opposition to the War was mostly among abolitionists who felt that the war was being fought to expand slavery. Among those who opposed the war were:
- Abraham Lincoln, who in his only senate term sponsored the so-call "spot resolutions" demanding to know exactly where American troops had been attacked and American blood shed - "Show me the spot."
- Henry David Thoreau who went to jail rather than pay taxes for a war he considered to be unjust and immoral.
- Former President John Quincy Adams also expressed his belief that the war was primarily an effort to expand slavery and was, in fact, a "most unrighteous war."

Goal #4: To learn how the Mexican population fared in "Occupied Mexico" 
The Mexicans who now lived in what many began to call "Occupied Mexico" did not fare well.
- They became alienated from the dominant, Anglo European society.
- They were politically unempowered.
- They became the target of racist violence because whites believed Mexicans posed a threat to the economy of the southwest.
- They were dispossessed of their land and subsequently went from being landowners to laborers. We get a really good idea of how this happened in the new state of California.
Mexican Land Dispossession in California
The early 1820s until the Gold Rush - Spanish and Mexican rulers granted over 800 large tracts of California land to Hispanic and white settlers. The rulers did not recognize Indian ownership of these lands. Newcomers to California selected valley locations with rich soil and reliable water sources to raise livestock and crops. Most grants were not accurately surveyed and mapped, which made the claims difficult to prove when California passed into American hands in 1848.
1848 - The Treaty of Guadalupe Hidalgo that formally ended the Mexican American War provided that the Mexican land grants would be honored (Article X). However, the United States Senate removed that protection when ratifying the Treaty. In order to investigate and confirm titles in California, American officials acquired the provincial records of the Spanish and Mexican governments.
In the ten years before the missions were dismantled, the Mexican government had issued only 50 grants for large ranchos. In the dozen years after the missions were secularized, over 600 new grants were made.
1851 - The California Legislature passed an "Act to Ascertain and Settle Private Land Claims in the State of California" which required all holders of Spanish and Mexican land grants to have their land titles confirmed by the newly-created Board of California Land Commissioners. Despite promises in the Treaty of Guadalupe Hidalgo, this Act placed the burden of proof of title on Spanish and Mexican landholders - and this was a difficult burden because in most cases, the land grants were made without closely defining the exact boundaries and even when boundaries were more specific, many markers had been destroyed before accurate surveys were made.
Although 604 of the 813 claims brought before the Land Commission were confirmed, most decisions were appealed to US District Court and some even went to the Supreme Court. The confirmation process required lawyers, translators, and surveyors, and took an average of 17 years to resolve - making it very expensive to defend land titles. In many cases, land had to be sold to pay for defense fees or given to attorneys in lieu of payment.
From the early 1850s forward - Before 1850, Mexican Californios owned all the land valued at over $10,000.
- By the 1870s they owned only one-fourth of this land; most Mexican ranchers had been reduced to farming rented property.
- By 1880, Mexicans were relatively landless in California.
- Upon losing their land, most Mexicans became laborers - on ranches, large farms, in the mines, and in railroad construction. All of the work was difficult, low paid, and often migratory.
- In the mines, for example - Anglo workers operated the machines, while Mexican miners did the manual and dangerous work. In the silver-mining industry in Arizona, white laborers received $70 a month plus board while Mexican laborers received $12 and $30 per month with no board.
- Work for Mexicans gradually became more exclusively labor involved.
- In 1850, 34% of the rural Mexican population in Texas were ranch or farm owners, 29% were skilled laborers, and 34% were manual laborers.
- By 1900, only 16% were ranch or farm owners, 12% were skilled laborers, and 67% were manual laborers.