Key Terms

alcalde: a Mexican official who often served as combined civil administrator, judge, and law enforcement officer
Barnburners: northern Democrats loyal to Martin Van Buren who opposed the extension of slavery into the territories and broke away from the main party when it nominated a pro-popular sovereignty candidate
Californios: Mexican residents of California
Compromise of 1850: Five laws passed by Congress to resolve issues stemming from the Mexican Cession and the sectional crisis
Corps of Discovery: the group led by Meriwether Lewis and William Clark on the expedition to explore and map the territory acquired in the Louisiana Purchase
empresario: a person who brought new settlers to Texas in exchange for a grant of land
filibuster: a person who engages in an unofficial military operation intended to seize land from foreign countries or foment revolution there
forty-niners: the nickname for those who traveled to California in 1849 in hopes of finding gold
Free-Soil Party: A political party committed to ensuring that white laborers would not have to compete with unpaid slaves in newly acquired territories
Liberty Party: a political party formed in 1840 by those who believed political measures were the best means by which abolition could be accomplished
Mexican Cession: the lands west of the Rio Grande ceded to the United States by Mexico in 1848, including California, Arizona, New Mexico, Nevada, Utah, and parts of Wyoming and Colorado
Missouri Compromise: an agreement reached in Congress in 1820 that allowed Missouri to enter the Union as a slave state, brought Maine into the Union as a free state, and prohibited slavery north of 36° 30' latitude
Northwest Passage: the nonexistent all-water route across the North American continent sought by European and American explorers
Slave Power: a term northerners used to describe the disproportionate influence that they felt elite southern slaveholders wielded in both domestic and international affairs
Tallmadge Amendment: an amendment (which did not pass) proposed by representative James Tallmadge in 1819 that called for Missouri to be admitted as a free state and for all slaves there to be gradually emancipated
Tejanos: Mexican residents of Texas
Wilmot Proviso: an amendment to a revenue bill that would have barred slavery from all the territory acquired from Mexico