After the United States became independent in 1776, it took advantage of European powers to compete for colonies in Africa and Asia, and expanded vigorously in the North American continent. In 1823, President James Monroe put forward the slogan "America is the America of the Americans" and established the basic national policy of expanding territory and dominating the Americas. Soon, the US government's aggressive eyes fell on Mexico, a neighboring country. In 1835, American immigrant slave owners in Texas, Mexico and California launched an armed rebellion. The Mexican government sent troops to suppress it. The United States directly intervened and supported Texas's declaration of independence the following year. In July 1845, American President James Polk, known for his frenzied expansion, officially announced the merger of Texas into the United States. Almost at the same time, Polk ordered General Zachary Taylor to lead a troop to quietly enter the Nueses River on the border between Texas and Mexico, looking for an opportunity to launch a war of aggression. In November of that year, Polk threatened Mexico with the return of US$3 million in debt to the United States, demanding that Mexico recognize the Rio Grande as the border between the two countries. The United States "buy" New Mexico and California for US$15-40 million. The Mexican government flatly refused.
On May 13, 1846, the US government declared war on Mexico, and the US-Mexico war officially broke out. Declaring war is nothing but a trick to deceive the world, and the military operations of the US military have been going on for more than four months before that.
In order to achieve the goal of attacking from north to south, dividing Mexican territory, and occupying its capital, in the first stage of the war, the US military decided to invade Mexico in three ways: one was commanded by Colonel Stephen Carney, responsible for the expedition to New Mexico and California; Commanded by the commander of the Slaughter fleet, responsible for blocking the coasts and ports of the Pacific Ocean and the Gulf of Mexico from the sea; the other route commander-in-chief, Taylor, headed directly to the Mexican capital Mexico City.
On May 18th, Taylor led his troops across the Rio Grande and captured the city of Matamoros. In June, Taylor's force expanded from 5,000 to 14,500. On July 14, its vanguard arrived at Chamargo, 1,000 miles north of Mexico City, and established a base for attacking Monterrey here. In the meantime, the Mexican government tried to negotiate with the United States, but the negotiations ended without a problem, and Mexican President Pasto also stepped down.
Beginning in mid-September, the US military has repeatedly launched attacks on the strategically important Monterrey, but under the tenacious resistance of the Mexican military and civilians, it has repeatedly failed. The arrogant Taylor had to change his attacking strategy, advancing side by side from the east and west sides of Monterey City with another U.S. army led by Walth, attacking in a roundabout way. After fierce fighting, on September 24, the US army finally broke through the city of Monterrey, and on the 25th, the Mexican army surrendered.
In the western region, a group of American immigrants living in the Sacramento Valley occupied Sannomine on June 14 and announced the establishment of the "Republic of California." On July 9th, the U.S. soldiers captured San Francisco and Santo Mino without blood. In less than a month, the US military occupied Santa Barbara and Los Angeles. On August 17, the US military announced that California had officially become a US territory.
During this period, the expeditionary force led by Carney arrived at Fort Bent at the intersection of the Arkansas River and the Santa Fe Trail in June and July 1846. Arrived in Las Vegas on August 15 and announced that New Mexico had become part of the United States. At the end of September, Carney led cavalry troops across Colorado into Southern California. On January 13, 1847, in San Fernando, the remnant Mexican armed forces surrendered to the U.S. Army. So far, the United States has invaded and occupied a large area of Mexico. Someone pointedly commented: "The U.S. military is like a black bear breaking into Mexico's cornfield. It's just that it's not rare and delicious corn, but the land is its only target."
Beginning in February 1847, the United States once again sent a large number of additional troops to the combat front, and the war entered the second phase. On March 9, US commander Scott mobilized 13,000 troops and equipped with 50 cannons. With the support of naval forces, he carried out an amphibious landing operation on Veracruz, the largest port on the east coast of Mexico. The morale of the 4000 Mexican soldiers stationed in the port was low, and they had no desire to fight, nor did they have naval support. The U.S. troops successfully landed without any casualties. Subsequently, the US army began to besiege Veracruz frantically. Beginning on March 22, 72 US warships and army artillery fired on Veracruz for several days. However, this time the US military was stubbornly resisted by the Mexican defenders, with 82 US casualties. Scott, annoyed and furious, ordered that if the Mexicans did not surrender, no living person would be allowed to leave the city. Under the fierce fire from the US army, Veracruz's blood flowed into a river. Seven days later, the U.S. forces captured the city.
After the capture of Veracruz, the U.S. army cleared the biggest obstacle to attacking Mexico City and accelerated its march. Mexican President Santa Ana hastily gathered 13,000 people to fight the US military in Cerro Gordo. On April 18, the U.S. army raided the left wing of the Mexican army through the dense forest of the valley and captured more than 3,000 people. St. Anna had to order a retreat. On May 15, the US military advanced to Puebla, 80 miles away from Mexico City. Because the upper class in the city surrendered and surrendered, the US military easily captured the third largest city in Mexico. On August 6, the U.S. soldiers approached Mexico City. Mexican soldiers and civilians, who had no way out, fought fierce battles with the enemy on the outskirts of the suburbs. But in the end because of outnumbered, the Mexican army retreated steadily. In order to seize the capital of Mexico, Scott personally led 7,000 men to launch a general offensive. At this time, 15,000 officers and soldiers had gathered in Mexico City, and the U.S. military was unable to succeed for a while. In desperation, on September 12th, Scott sent men to attack the 200-foot-high Chapultepec Hill fortifications in an attempt to control Mexico City from a commanding height. Facing the tide of the U.S. military's offensive, the students of the Mexican Military Academy stationed here fought bloody battles, and the U.S. troops were killed and wounded everywhere. On the evening of September 13, Mexican President Santa Ana led government members to retreat hurriedly, and the city was in chaos. At dawn on September 14, the US army took the opportunity to invade the city. In order to show his prestige, Scott ordered the US military officers and soldiers to wear brand-new uniforms to hold a grand ceremony to enter the city, but they were suddenly shot violently by the Mexican army and suffered heavy casualties. After entering the city, the U.S. and the Mexican army engaged in a full day of fierce street fighting. It was not until September 15 that they completely controlled Mexico City after more than 860 casualties.
After the fall of Mexico City, the brave and unyielding Mexican people launched a large-scale guerrilla war with the occupiers. In desperation, the US military mobilized 20,000 people to fight against the guerrillas and brutally suppressed the resistance of the Mexican people. The Mexican government could have seized the opportunity to organize a counteroffensive and turn defeat into victory. But the Mexican rulers blindly compromised, dismissed Santa Ana’s presidency and established a new government with Peña as the interim president. After Peña came to power, he immediately called on the United States to hold peace talks. On February 2, 1848, the United States and Mexico signed the Treaty of Guadalupe Hidalgo. The United States has seized nearly half of Mexico's territory, totaling approximately 2.3 million square kilometers. This is today most of the states of California, Nevada, Utah, Arizona, and New Mexico, as well as part of Colorado and Wyoming. The United States only paid Mexico $15 million as "compensation."
Through the US-Mexico War, the United States became a transatlantic and Pacific power, and has since become the dominator of the Americas. Even Grant, an American star who took part in the war himself, had to admit: "This war is one of the most unjust wars waged by a powerful nation against a weaker nation."