February 2, 1848 – The war between the U.S. and Mexico (the Mexican-American War) ended with the signing of the Treaty of Guadalupe-Hidalgo. In exchange for $15 million, the U.S. acquired the areas encompassing parts or all of present-day California, Nevada, Utah, Arizona, New Mexico, Colorado, Wyoming, and Texas. The U.S. started the war to acquire those territories when Mexico refused to sell. The treaty was ratified on March 10, 1848.
Mexico, which gained its independence from Spain in 1821, spanned a vast area from Central America to modern-day Oregon. The northern half of Mexico included California and the modern US Southwest -Texas, New Mexico, Arizona, Nevada, Utah, and parts of Oklahoma and Colorado. The area was sparsely populated by Mexican citizens, and in the 1820’s the Mexican government invited Americans to settle in Texas, in the hopes that their presence would help stabilize the area in the face of Indian hostility.
The Mexican government’s offer of free land enticed thousands of Americans to emigrate to Texas, bringing their slaves with them as well. By the early 1930’s this influx of American slave-owners began to grate on Mexican authorities, and government efforts to reign them in only exacerbated conflict. By 1835 both white Texians and Mexican Tejanos joined together and declared Texas’ independence from Mexico. The ensuing war for independence ended in 1836 with the then Mexican dictator, Santa Anna, signing the Treaties of Velasco which acknowledged Texas’ independence.
When Texas subsequently asked to be annexed by the United States, the US Congress balked, however. Not only did the Mexican government reject the Treaties of Velasco and refuse to acknowledge Texan independence, they also contested the boundaries claimed by Texas. Congress was worried that if they were to annex Texas, Mexico would have no choice but to declare war on the US.
Enter James Polk, elected president in 1844. Polk was a firm believer in Manifest Destiny and the annexation of Texas. After his election his supporters in Congress finally annexed Texas before he was even inaugurated. Polk was not concerned about war with Mexico – in fact, he courted it. Such a war, in Polk’s twisted world view, would allow the US to take not only Texas but all of Northern Mexico, including California and the Southwest, and fulfill Manifest Destiny’s vision of an America which stretched from coast to coast.
Soon after Polk’s inauguration in March 1845, he began looking for an excuse to invade Mexico. First, he sent a government official, John Slidell, to Mexico to offer to buy California and the New Mexico Territory for $30 million. Mexican officials, however, still angry over the American annexation of Texas, refused to even meet with the Slidell. Polk, who was counting on such a reaction, publicly announced that the Mexican response was a terrible insult to the United States, and “an ample cause of war.”
At the same time, Polk tried to provoke the Mexicans into attacking American troops to give him a better excuse for a declaration of war. In January of 1846, Polk sent General Zachary Taylor and 2,000 soldiers to occupy the disputed territory on the Mexico/Texas border. Taylor built a fort just across from the Mexican border in that disputed area, near the Rio Grande River, and waited. When the Mexican authorities demanded that he leave, Taylor refused. Polk had told Taylor to stay put, hoping that the Mexicans would take the bait and attack Taylor’s men.
Polk got his wish in April of 1846, when Mexican cavalry crossed the Rio Grande and attacked an American patrol, killing eleven of Taylor’s men. Polk now had his excuse for war. On May 11, 1846, he formally requested that Congress declare war on Mexico, claiming that war had already begun by “the act of Mexico,” since Mexico had, “invaded our territory and shed American blood on American soil.”
Polk’s request for a declaration of war was jaw-dropping for its disregard of the facts. For one, the fight occurred on land claimed by both countries and was by no means undisputed “American soil.” For another, Polk claimed that he had done everything he could to keep the peace with Mexico, when, of course, he had purposely provoked the attack. All that was missing was a claim that Mexico was hiding weapons of mass destruction.
As is always the case when the country is “attacked,” however, patriotic fervor arose, and Congress quickly gave Polk his declaration of war. Although many northern Whig Congressmen opposed the war, few actually voted against the declaration for fear that they would lose re-election. The Mexican-American War had begun.
Still, not all of the country supported the war. Generally, people in the South and West, who wanted more farmland, favored it. On the other hand, many northerners opposed the war, fearing that it was simply an excuse to gain more land onto which to expand slavery (which it was). A few bold northern Congressmen publicly challenged Polk’s claim of an attack on American soil, arguing that the American soldiers had actually been attacked across the Rio Grande, in Mexico. Even when the war was already winding down, young Whig Congressman Abraham Lincoln from Illinois demanded that Polk explain exactly where the “spot” on American soil was that the American soldiers were attacked. Lincoln’s “Spot Resolutions” were largely ignored, and Lincoln lost his bid for re-election the next year.
In the war itself, the better equipped, trained and led American forces made quick work of their Mexican counterparts in California and the Southwest. The New Mexico territorial capital of Santa Fe surrendered without a shot being fired. In California, on June 14, 1846, 30 American setters (who had spent the night before drinking heavily) surprised the few Mexican soldiers stationed at the local headquarters in Sonoma and took control of the town and fort. They declared the creation of the California Republic, raising a flag containing a crude drawing of a bear and star to represent their new “Bear Republic.”
On July 7, a fleet of U.S. warships captured Monterey, California, and sent word that California was now under the control of the United States. The Bear Flag was replaced with the American flag, signaling the demise of the Bear Republic. The only real fighting in California was in Los Angeles, where Americans and local Californios (Californian Mexican citizens) battled back and forth for control of the City. Finally, in January of 1847, the American forces prevailed, and the Treaty of Cahuenga was signed, ending the fighting in California.
The invasion of Mexico itself proved somewhat more difficult. The initial invasion force of 6,000 men was led by General Zachary Taylor. Taylor’s troops marched down from Texas and attacked the Northern Mexican city of Monterrey in September of 1846. For two days, 10,000 Mexican defenders held off the Americans from entering the city, inflicting serious casualties. On the third day of the battle, the Americans managed to enter the city and fierce hand-to-hand combat in the streets followed.
The Mexican commander, General Pedro de Ampudia, finally negotiated a truce with General Taylor, who agreed to a two month cease-fire during which Ampudia and his remaining troops could leave the city. When Polk learned of the deal he exploded in anger, yelling that Taylor’s only job was to “kill the enemy.” Taylor’s humanity ended up costing him his command, as the furious Polk replaced him with General Winfield Scott.
In March of 1847, Scott and his army of 12,000 soldiers captured the city of Veracruz. Yellow fever began to take its toll, however, and in September when he marched on the capital, Mexico City, he was down to 8,500 men. Just outside the city he ran into a force of 12,000 Mexican soldiers under the command of Mexican General Santa Anna, who tried to prevent Scott from entering the city. Even with his dwindling forces, Scott was able to rout Santa Anna, and advanced on to the capital.
At the city’s walls, Scott’s forces met fierce resistance at an old castle named Chapultepec, which was defended by only 400 men, most of whom were young Mexican military cadets. Even after the Americans took the castle, six cadets refused to surrender, and fought to the death instead. One cadet wrapped himself in the Mexican flag and leapt from the castle wall to his death, rather than let the flag be captured. These six cadets are honored in Mexico today as the “Los Niños Héroes,” the “Child Heroes.” By September 15, 1847, Mexico City finally fell to the Americans, and the Mexican government gave up. The war was over.
The killing, unfortunately, was not. A particularly gruesome spectacle followed the capture of Chapultepec. Earlier in the war, a group of Irish-American U.S. soldiers who were angry over prejudice against Catholics in the United States had deserted from the U.S. army. These soldiers then joined up with the Mexicans, who were fellow Catholics, and formed what was known as the Saint Patrick’s Battalion of the Mexican Army.
Before arriving in Mexico City, Scott’s troops had captured about 50 men of the Saint Patrick’s Battalion. These prisoners were brought along to Mexico City by Scott’s soldiers. After Scott’s forces captured Chapultepec, he ordered that all 50 men be publicly hanged, en masse, as traitors. Despite pleas from the Mexican government and the Pope for leniency, the hanging went on as scheduled.
On February 2, 1848, Mexico and the United States signed the Treaty of Guadalupe Hidalgo, formally ending the war. Mexico gave up nearly half of its territory – more than 500 thousand square miles. This included all claims to Texas, California, and the New Mexico Territory (most of modern day New Mexico, Utah, Nevada, Arizona, and Colorado). Mexico also agreed to the Rio Grande as the boundary between the US and Mexico, thereby resolving the old dispute between the border of Texas and Mexico.
In exchange, the United States paid Mexico $18 million and agreed to protect the rights of former Mexican citizens living in those territories (this last clause, however, was struck from the Senate when it approved the treaty). Mexican citizens had the choice of leaving what was now the US and relocating to Mexico, or staying and becoming US citizens (over 90% chose to stay).
Some Senators opposed the treaty, arguing that the entire war had been unjust, and the United States was not entitled to any land other than Texas. Others opposed the treaty because it gave the United States too little – they wanted all of Mexico. In the end, however, the treaty fulfilled most Senators’ visions of Manifest Destiny, and it was ratified by a vote of 38-14.
While the Treaty specifically honored the existing property rights of (now) former Mexican citizens living in the new US Territories, those promises proved hollow. While old Spanish and Mexican land grants were supposed to be honored, they were often ignored by American courts and unlawfully extinguished.
For instance, in 1851 Congress passed the California Land Act, which established a special Board of Land Commissioners to review land claims in California. The Board required that anyone claiming land under an old Spanish or Mexican land grant had to present their claim to the Board – located in San Francisco – and have specific documented proof to back it up. This required Californios to travel to San Francisco, hire English speaking lawyers to argue their cases, and have sufficient written documentation to back up their claims, or they would lose their land. Even for those who were able to do so, the cost of the process, along with high real-estate taxes imposed on large land grants, forced many to sell much of their land to speculators.
On the other hand, these newly acquired lands in the Southwest were made open to slavery by the Compromise of 1850. The fight over the spread of slavery into these new territories, within 10 years, would lead directly to the Civil War.