Causes and background[change | change source]
When Mexico got independence from Spain in 1821, Texas was part of Mexico. Americans and other settlers came into Texas when Mexico allowed non-Spanish settlers to settle there. After many settlers came to Texas, disputes led to the Texas Revolution in which Texas became independent. Mexico refused to recognize the Republic of Texas as an independent country. Texas soon asked to become a state of the United States. Years later, in 1845, the US annexed Texas, and Mexico broke off diplomatic relations. The United States offered to buy from Mexico the land extending from Texas to the Pacific Ocean, but Mexico wanted to keep that vast area. In 1846, a dispute over the border between Texas and Mexico resulted in armed conflict, and the Mexican–American War began.
Some maintain that the United States provoked the border dispute so they could win the territory that Mexico would not sell. There was strong sentiment in the United States that the country was destined to expand to cover the entire continent; We could see in the name "United States of America", considerating that America is a continent.
Fighting[change | change source]
In addition to small units sent to California and New Mexico, the United States sent two major armies into Mexico under the commands of General Winfield Scott and future President of the United States General Zachary Taylor.
After the U.S. had entered Mexico, the Mexican general Antonio López de Santa Anna took command of the Mexican soldiers in early 1847. The U.S. forces fought Santa Anna near Monterrey and Buena Vista. After Buena Vista, the Mexican army had many problems, including starvation, disease, and desertion. The Mexican government was unstable. In March 1847, Scott landed at Veracruz. His force included future Civil War generals Robert E. Lee, Ulysses S. Grant, Stonewall Jackson and George G. Meade, as well as Commodore Perry. Scott took Puebla in May, and took Mexico City in September after the battle of Battle of Chapultepec.
When American soldiers came to California, the Bear Flag Revolt was happening. Some Californians were attempting to leave Mexico and form their own country, as Texas had done. In July and August 1846, American soldiers captured Monterey, Yerba Buena and Los Angeles. After a counterattack by the Californios, the Americans had taken much of California by 1847. The Mexican governor of California, Pio Pico, left the state.
Peace and aftermath[change | change source]
The United States won the war and Mexico signed the Treaty of Guadalupe Hidalgo in 1848. The treaty gave the U.S. lands that would become the states of Arizona, California, New Mexico, Nevada, Utah, southwestern Colorado, and southwestern Wyoming. Mexico received 15 million dollars and gave up its claims to Texas.
The slavery debate in the United States became more intense with the addition of the new territory and the question of whether slavery would be legal in these new territories. Also, many of the officers who would lead troops in the American Civil War fought in the war and would use their experiences in the coming Civil War.