The Election of 1844 and US-Mexico War

expansionists gain control of the Democratic Party
they nominate James K. Polk (Tennessee)
- staunch pro-slavery expansionist
platform: “the reoccupation of Oregon and the reannexation of Texas”
- appeals to the Northern and Souther expansionists
Polk narrowly wins
Tyler pushes Texas annexation through Congress via the Joint Resolution, days before leaving the White House
Mexico severs diplomatic relations

contested Texas border
Polk sent the United States Army into disputed territory, 1845
April 24, 1846, skirmish on Rio Grande which led to battles
- United States Congress declared war on May 13
United States invaded and occupied the northern Mexico, 1846-48
- claimed New Mexico and California as conquered United States territory
- Mexico refused to surrender
March 1847, the United States invaded central Mexico by the sea
- captured Mexico City in September
- still there was no surrender

the United States negotiator Nicholas Trist agreed to a smaller territorial cession against Polk’s orders
Treaty of Guadalupe Hidalgo, 1848
- Mexico cedes nearly 1/2 of it’s territory, acknowledges Texas annexation
- United States pays $15 million to Mexico + $3.75 million to the United States citizens with claims against Mexico
- 500,000+ square miles at 5 cents per acre (not counting Texas)
1848, Gold Rush sends thousands to California
conflict over the expansion of slavery into new territory began immediately