May 13: U.S. Congress Declares War on Mexico (1846)
Prayer Idea
Pray that the United States would pursue peace and cooperation with its neighbors.
History Note
Texas gained independence from Mexico in 1836 and became a separate country. Many people in Texas wanted to become part of the United States, but the government of Mexico opposed this.
James K. Polk won the 1844 U.S. presidential campaign with a goal to expand the territory of the United States to the Pacific Ocean. Outgoing President John Tyler signed legislation to allow Texas to became a state on March 1, 1845, just before Polk took office. Texas joined the Union in December of that year.
Mexico did not recognize the annexation of Texas, nor did it recognize the Rio Grande as the southern border of Texas. Mexico said the Nueces River, which lay further north, was the true border. Polk tried to negotiate with Mexico over the purchase of Texas, California, and all of the territory between them; but Mexico was insulted by the Texas annexation and refused to negotiate.
Polk sent American troops to the Rio Grande area, Mexican forces attacked them, and the United States declared war on May 13, 1846. Many Americans, particularly in New England, opposed the war as an expansionist and pro-slavery move. They called it “Mr. Polk’s War.” The Whig Party won a majority over President Polk’s Democratic Party in the U.S. House in the 1846 mid-term election, largely because of widespread unhappiness over the war with Mexico.
The U.S. Army defeated Mexican forces in Texas and then invaded Mexico. The Americans captured Mexico City in September of 1847. Meanwhile, a group of Americans in Sacramento declared the independent Republic of California in June of 1846. A month later, the U.S. Navy Pacific fleet took control of the situation on the Pacific Coast and claimed California to be a territory annexed to the United States.
The war ended with the signing of a treaty in February of 1848. The United States got Texas, California, and the area in between, which became Arizona and New Mexico, for $15 million. The U.S. also agreed to take over claims that individual Americans had against the Mexican government to a total of about $3 million. The treaty gave the U.S. the largest increase in its land area since the Louisiana Purchase, and it brought under U.S. control about as much territory as Jefferson’s deal had.
The conflict saw the first use of war correspondents reporting back to American newspapers using telegraph lines. The Mexican-American War was also the first to be documented by photography. Many West Point graduates who fought together against the Mexicans later saw combat in the Civil War on opposite sides. These military officers included such men as Robert E. Lee, Ulysses S. Grant, Thomas (“Stonewall”) Jackson, George McClellan, Braxton Bragg, and George Pickett.
An unknown photographer took several dozen photographs of U.S. soldiers and of scenes in Mexico during the war. This daguerreotype shows the grave of Lt. Col. Henry Clay Jr. in Mexico. Henry Clay was a prominent politician from Kentucky. His son, Henry Clay Jr., was one of about 13,000 Americans and perhaps 25,000 Mexicans who died during the war. Image courtesy the Amon Carter Museum of American Art, Fort Worth, Texas.
Learn More
This video provides an overview of the Mexican-American War.
Please Note: There are illustrations of battles.
Find other resources at Homeschool History.
