Westward Expansion, Manifest Destiny & Contested Land — Print · Grade 7 Social Studies

Part 1 · Texas

Mexico, newly independent and wanting its northern province settled, invited American colonists in the 1820s on terms: become Mexican citizens, adopt Catholicism, and obey Mexican law — which from 1829 prohibited slavery. Thousands came, mostly from the southern states, and brought enslaved people anyway under long-term indenture contracts that fooled nobody.

By the mid-1830s there were far more Anglo settlers than Mexican residents in Texas, and when the government in Mexico City moved to centralise authority, they revolted. In 1836 a Mexican army under Santa Anna besieged a mission at San Antonio for thirteen days; the roughly two hundred defenders of the Alamo were killed to a man. Six weeks later Sam Houston surprised and destroyed the Mexican army at San Jacinto and captured Santa Anna himself.

The Alamo’s afterlife is as interesting as the siege. Remember the Alamo became a rallying cry within weeks and the mission became a shrine, with Davy Crockett and Jim Bowie turned into folk heroes. What the story usually leaves out is that the Texan cause included the right to hold people as property against Mexican law, and that among the defenders were men who had come to Texas precisely because land there was cheap and slavery was tolerated in practice. A monument can be accurate about courage and silent about purpose.

Texas existed as an independent republic for nine years, and the delay was about slavery. Annexing a vast slaveholding territory would upset the balance in the Senate, and northern politicians blocked it until 1845. Mexico had never recognised the independence and warned that annexation meant war. It did.

Part 2 · The war, and the people who objected to it

President Polk had campaigned on expansion and wanted California. He offered to buy it; Mexico refused to receive his envoy. He then ordered troops into disputed ground between the Nueces and the Rio Grande, where a Mexican patrol attacked them, and told Congress that American blood had been shed on American soil.

The claim was contested at the time by people who are not usually remembered as radicals. A freshman congressman named Abraham Lincoln introduced the Spot Resolutions, demanding Polk identify the exact spot where the attack occurred and whether it was American territory. Henry David Thoreau went to jail rather than pay a tax supporting the war, and wrote *Civil Disobedience* about it. Ulysses S. Grant, who fought in the war as a young officer, called it in his memoirs one of the most unjust ever waged by a stronger nation against a weaker.

The Treaty of Guadalupe Hidalgo in 1848 transferred California, Nevada, Utah and most of Arizona and New Mexico. The roughly 100,000 Mexican citizens living there were promised citizenship and protection of their property; in practice Californio landholders spent decades in American courts defending titles and mostly lost them.

Part 3 · Gold

On 24 January 1848, a carpenter named James Marshall found flakes of gold in a millrace at Sutter's Mill on the American River. The Treaty of Guadalupe Hidalgo was signed nine days later. Mexico ceded California without knowing what had just been discovered in it.

The news took months to travel and then moved everything. Around 300,000 people reached California in the next few years, from the eastern states, from Mexico, Chile and Peru, from China, Ireland and Australia. San Francisco went from a settlement of a few hundred to a city of tens of thousands in two years. Ships were abandoned in the harbour by crews who had deserted for the diggings.

The diggings were also more diverse than the legend suggests, and the law followed quickly to make them less so. Chinese miners arrived in large numbers from 1849, as did Mexicans, Chileans and Peruvians with real mining expertise, and California responded with a Foreign Miners Tax in 1850 charging twenty dollars a month to anyone not a United States citizen — aimed first at Latin American miners and later enforced overwhelmingly against the Chinese. Most gold-seekers made little; the reliable fortunes were made selling shovels, flour and passage.

For California's Native peoples the Gold Rush was a catastrophe with few parallels. Miners drove them off land, destroyed the salmon runs and oak groves they lived on, and conducted organised killings that the new state government funded and the first governor openly described as a war of extermination. The Native population of California fell from something like 150,000 in 1848 to around 30,000 by 1870.

Part 4 · Every acre raised the same question

Almost as soon as the war began, a Pennsylvania congressman named David Wilmot proposed that slavery be barred from any territory acquired from Mexico. The Wilmot Proviso passed the House repeatedly and never the Senate, where the sections were evenly balanced. It settled nothing and it clarified everything: the real argument was no longer about slavery where it existed but about slavery where it did not yet.

California forced the issue almost immediately. The Gold Rush population was large enough to apply for statehood by 1850, skipping the territorial stage, and it applied as a free state — which would break the Senate balance of fifteen and fifteen. That application is what produced the Compromise of 1850, the first unit of the next chapter.

The Mormon migration belongs in the same decade and shows another face of expansion. Driven out of Missouri and then Illinois by mob violence, and with their leader Joseph Smith murdered in 1844, some fifteen thousand members of the Church of Jesus Christ of Latter-day Saints crossed the plains under Brigham Young from 1846 and settled the Salt Lake valley — then Mexican territory, which became American two years later. People moved west to escape the United States and found it had followed them.

This is the pattern for the next decade, so it is worth fixing now. The country acquires land; the land must be organised; organising it requires deciding about slavery; neither section will accept the other's answer; a compromise is improvised; the next acquisition destroys it. Expansion did not cause the Civil War on its own, but it is what made the question impossible to postpone.