The American-Mexican War between the United States and Mexico began when Mexicans attacked American troops on the southern border of Texas on April 25, 1946. When American General winfield scott occupied Mexico City on September 6th, the fighting ended. A few months later, the peace treaty was signed in Guadalupe Hidalgo (February 2, 1848). In addition to admitting that the United States annexed Texas, defeated Mexico and ceded California and New Mexico (including all the southwestern States today) to the United States.

The war between the United States and Mexico was the first major conflict driven by the idea of "destiny is determined by heaven"; I believe that the United States has the natural right or destiny to expand the national boundary from "ocean to glorious ocean". This belief will eventually bring great pain to many Mexicans, Native Americans and American citizens. After the early war of independence of Texas from Mexico, with Texas finally becoming a state of the United States, the tension between the two largest independent countries on the North American continent intensified. The argument about the B-line triggered a military confrontation, which was further aggravated by the fact that President Polk was eager to seek war to seize a large area of land from Mexico.

Like all major events, there are different historical explanations about the causes of the Mexican war. To put it simply, because the United States annexed Texas (1845), Mexico's authoritarian central government launched a war. Although the independent Republic of Texas was established 10 years ago, Mexico continued to claim sovereignty over it. However, some historians believe that the United States provoked this war by annexing Texas and stationing troops at the mouth of the Rio Grande more premeditated. Another related explanation is that President James K. Polk's administration forced Mexico to go to war in order to seize California and Southwest China. A few people think that this war is only because Mexico failed to pay the claims for losses suffered by American citizens during the Mexican War of Independence.

The American-Mexican War is a traditional war to a great extent. The traditional army composed of infantry, cavalry and artillery used the established European style tactics to fight. As the American army went deep into the center of Mexico, some defense forces used guerrilla tactics to harass the invaders, but these irregular forces did not have a great impact on the outcome of the war.

After the hostilities began, the US military adopted a three-pronged strategy aimed at seizing control of northern Mexico and forcing an early peace. Two American troops moved south from Texas, while the third army led by Colonel stephen kearny moved west to Santa Fe, New Mexico, and then to California. In a series of battles between Palo Alto and Rezaca de Palma (near Brownsville, Texas today), General Zachary Taylor's army defeated the Mexican army and began to move south after causing more than 1,000 casualties. 1846 In July and August, the US Navy captured Monterey and Los Angeles in California. 1846 In September, Taylor's army and General Ampudia's army fought a three-day bloody battle for control of the northern Mexican city of Monterrey. After the Americans occupied the city, the two sides reached a temporary truce, which enabled both sides to recover from the tired battle of Monterrey. During this period, former President Santa Anna returned to Mexico from exile and formed and trained a new army of more than 20,000 people to resist the invaders. Despite losing a large area of land and losing several major battles, the Mexican government refused to make peace. For Polk's government, it is obvious that only a complete victory on the battlefield can end the war. The continuous fighting in the arid desert of northern Mexico convinced the United States that the land expedition to occupy the enemy capital Mexico City would be dangerous and difficult. To this end, General winfield scott proposed the largest amphibious landing in history and the battle to seize the Mexican capital.

Consequences of the conflict:

1. The United States acquired the northern half of Mexico. This area later became California, Nevada, Arizona, New Mexico and Utah.

After the war, President Santa Anna lost power in Mexico.

3. American general Zachary "Old Rough and Ready" Taylor used his reputation as a war hero to win the presidency in 1848. The real irony is that Democratic President Polk pushed the war and led Whig Taylor to the White House.

In the following decades, the relationship between the United States and Mexico has been very tense, and several military conflicts have occurred on the border.

For the United States, this war provides a training base for those who lead the northern and southern armies in the coming American Civil War.

A unique fact or trend:

1. This war is the first large-scale amphibious landing in the history of American troops.

The defeat of Mexico was the first time that the enemy occupied the capital of the country. The French will also occupy Mexico City in A.D. 1860.

Although it was very popular at home in the early days, the symbol of the war was the growth of a resounding anti-war movement, including Ralph Waldo Emerson, a famous American, former President john quincy adams and Henry David Thoreau. The center of anti-war sentiment revolves around New England and is directly related to the movement to abolish slavery. Texas became a slave state after joining the Union.

4. An interesting aspect of this war involves the fate of Irish deserters from the American army who joined the Mexican army as St Patrick's Camp. This group of Catholic Irish immigrants resisted the abuse of American-born Protestant officers and the way the American army treated Catholic Mexicans. In this period of American history, Catholics are an abused minority, and Irish are an unpopular nation in the United States. 1In September, 847, the US Army hanged 16 surviving members of St. Patricio as traitors. To this day, they are still regarded as heroes of Mexico.

In Mexico, people will remember a special day to celebrate the bravery of young cadets in Chapultepec Castle Military Academy, which was attacked by Scott's army on September 13 and 1847. "Dia DE Ronnie? Osheroes de Chapultepec ("Chapultepec Boy Hero Day") is celebrated every year on the anniversary of the battle.

Under the command of the commander, these young students joined the battle-the young heroes who are commended every year are four teenage students (Francisco Marquez, the youngest 13 years old! ) and their lieutenant squadron leader Juan de la varela (the oldest, 20 years old), who were killed in that battle.

Until 1880, the "Republican campaign textbook" of the Republican congressional Committee described this war as "dirty and corrupt" and "one of the darkest scenes in our history-this war was forcibly imposed on us and the Mexican people by Pre' ST Polk in pursuit of the territorial expansion of slave oligarchy".

This is summed up from different resources. Detailed war background and description can refer to Wikipedia, hoping to help you.