Mexican American War

In 1846, main hostilities between the United States and Mexico had begun. The boundaries between Mexico and the U.S. were under dispute. A few years back, 1800 men of the Spanish Army, lead by Antonio Lopez de Santa Anna, was leading an attack on America on February 23, 1836. The only thing to stop the attack in time for the other Americans to get supplies, was the fort the Alamo. The 200 men in the Alamo were successfully able to hold off the Spanish for thirteen days - enough time for the U.S. to strengthen their defenses (As a call of revenge, Americans would say "remember the Alamo"). This was only one of the many battles of the war.
President James T. Polk was the present president of the time. He had a great aggressive desire to bring California and New Mexico under American control. This was one of the reasons the war started. Polk sent messengers to Texas for an immediate annexation, but Mexico wouldn't let go of Texas without fighting back first, and America wasn't able to gain control of Texas yet. Something that made everything worse was that most of the Americans believed in the Manifest Destiny (belief of God-given right to control the entire continent). The Americans also approved of the war because they wanted the United States to gain control of as much land as they could.
President Polk had later ordered the Slidell Mission. Sending John Slidell as a messenger, he went to make an acquisition of buying New Mexico and California from Mexico, but the attempt failed. He had also advanced troops into the Rio Grande, but that didn't help to obtain California. April 24, 1846- Mexican soldiers attacked an American troop, killing and injuring 16, capturing the rest. On May 13, 1846, America declared war on Mexico.
President Polk first wanted to capture some part of California. On January 1847, 500 rounds of cannon shells were fired on Bajah California, until the United States was able to take control of it. Seeing the Importance of California, its conquest was easy. In 1840-1841, a French attache' visiting, reported that "whatever nation that chooses to send a man-of-war and 200 men" could take California. (Christens 92) California was still under Mexican government, but the Californians didn't quite like it, so hey started to rebel. Rebellion came in 1936, and the rebels overthrew the governor. The rebels - and some U.S. and English settlers - eventually accepted the centralist Constitution. Mexico City rewarded the leaders - Jose' Castro, Juan Baustita Alvarado, and Mariano Guadalupe Vallejo - with land grants and political power. Alvarado became governor, and Castro became military chief.
Immigrants that lived in California could only live in the inland valleys. The Sacramento Valley became home to many immigrants, because they could settle around Sutter's Fort, which was a successful trading business. Captain Jon C. Fremont, between 1842 and 1853, had led five well-publicized expeditions to the West. He was in the center of a rebellious group of U.S. immigrants, and his activities there incensed Mexican authorities, and inspired what would be called the Bear Flag Revolt. (Christens 97) A small group of armed men had taken over General Vallejo's encampment without resistance. The rebels attempted to expand their revolution, but they didn't get far because they were stopped by Castro's troops.
During the war, the northeastern states were afraid of the new states coming in to the United States would be slave states. Also during the war, there obviously were many battles. On January 27, 1847, Santa Anna sent in 20,000 soldiers from San Luis Potossi to attack General Zachary Taylor, for Santa Anna had learned that Taylor had lost more than half of his army. (Christenson 152-153) Santa Anna marched his troops to Agua Nueva expecting Taylor's troops, but when he found it abandoned, he ordered his men to move on. When the Mexican soldiers left, later, Taylor came back to drill his soldiers in Agua Nueva, but eventually left for Buena Vista when the Mexican troops were closing in on their location. The Americans went into a defensive position, waiting for the attack. The three-day battle was a hard one, until the third day, Santa Anna gave the order to have his men retreat. After that battle, there were other battles, like at Varecuz, Cerra Gordo, and a few others. Even though there were lots of other battles, the most famous and important one was the battle at Mexico's capital, the Battle of Mexico City. Here, there was lots of fighting, and sometimes Mexico would lead in winning, and sometimes vise versa with the U.S. On the early morning of September 13, 500 men volunteered to scale the walls of Mexico City's castle, and then attack. This group of men was called the Forlorn Hope. Meanwhile, there was a diversion attack on the other side of the castle to distract the Mexican army from defending the sneak-attack. By approximately 9:30 AM, the battle was over and the U.S. captured Mexico City, the Capitol of Mexico.
Five months after that last battle, the war was finally over. The United States gained control of what are present-day California, Nevada, New Mexico, Texas, and Arizona. The treaty that ended the war, the Treaty of Guadeloupe Hidalgo, was signed. Even though it appears that the U.S. won the war, there really were no complete winners. There were casualties on both American side and Mexican side, and there were a few towns/forts destroyed. Although it should be avoided constantly, war is needed for only certain things, like in the Mexican/American War.