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Treaty of annexation
In 1844, President John Tyler restarted negotiations with the Republic of Texas, culminating with a Treaty of Annexation. The treaty was defeated by a wide margin in the Senate because it would upset the slave state/free state balance between North and South and risked war with Mexico, which had broken off relations with the United States. -
Polk as president
Pres. James K. Polk, was elected in 1844. He sent troops from the US were moved into the disputed territory of Coahuila. These troops were then attacked by Mexican troops, killing 11 American troops and taking 52 prisoners. These same Mexican troops later laid siege to a US fort along the Rio Grande. -
Polk ordering troops
But shortly before leaving office and with the support of President-elect Polk, Tyler managed to get the joint resolution passed on March 1, 1845. Texas was admitted to the union on December 29. While Mexico didn’t follow through with its threat to declare war, relations between the two nations remained tense over border disputes, and in July 1845, President Polk ordered troops into disputed lands that lay between the Nueces and Rio Grande rivers. -
sending John Slidell to Mexico
In November of 1845, Polk sent the diplomat John Slidell to Mexico to seek boundary adjustments in return for the U.S. government’s settlement of the claims of U.S. citizens against Mexico and also to make an offer to purchase California and New Mexico. After the mission failed, the U.S. army under Gen. Zachary Taylor advanced to the mouth of the Rio Grande, the river that the state of Texas claimed as its southern boundary. -
Zarchary Taylor Attack
On January 1846 at Rio Grande River Zachary Taylor and 4000 men were sent to disputed territory, expecting attack. Conflict with Mexican troops results in 16 American casualties. -
Polk asks to declare war with Mexico
Mexico, considered Taylor’s army an act of aggression and in April 1846 sent troops across the Rio Grande. Polk, in turn, declared the Mexican advance to be an invasion of U.S. soil, and on May 11, 1846, asked Congress to declare war on Mexico, which it did two days later. -
Polk asks for war
On May 1846 at Washington D.C Pres. Polk asks for war with Mexico. Northern Whigs fear victory would add more slave states to U.S. Declaration passes 40-2 in Senate, 174-14 in House. Whig Congressman Lincoln asks for the spot on American soil where American blood was shed. -
Battle of Monterey
On July 7, 1846 General Taylor’s army followed the Mexican troops to Monterey and fought to take control of this city. “The fighting was fierce. In the end, it came down to hand-to-hand combat in the city streets. But again, the American army was victorious.” This battle was the Battle of Monterey. -
Mexico City Battle
On September 12-14, 1847 General Winfield Scott and troops arrived in Mexico's capital city and fight their final battle against a wearied Mexican army. The victory and occupation of the city by the U.S. on Sept. 14 marks the unofficial end of the Mexican-American War. This battle was the Battle of Mexico City. -
Treaty of Guadalupe Hidalgo
After nearly two years of fighting, peace was established by the Treaty of Guadalupe Hidalgo, signed on February 2, 1848. The Rio Grande was made the southern boundary of Texas, and California and New Mexico Were ceded to the United States.
