The Mexican-American War and Its Consequences

The Mexican-American War (1846-1848) was a direct result of American expansionist policies and the annexation of Texas. President Polk's actions, including sending troops into disputed territory, ultimately led to conflict with Mexico.

Vocabulary: Sectionalism refers to the division between Northern and Southern states over issues such as slavery and states' rights.

The Treaty of Guadalupe Hidalgo ended the war in 1848, resulting in significant territorial gains for the United States. This included the present-day states of California, New Mexico, and the confirmation of Texas as part of the U.S.

Highlight: The Mexican Cession added vast new territories to the United States, intensifying debates over the expansion of slavery.

The Wilmot Proviso, though never passed, proposed banning slavery in any territories acquired from Mexico. This proposal heightened sectional tensions and foreshadowed future conflicts over slavery's expansion.

Quote: "The United States will conquer Mexico, but it will be as the man swallows the arsenic, which brings him down in turn. Mexico will poison us." - Ralph Waldo Emerson, reflecting on the consequences of the Mexican-American War.

The Gadsden Purchase of 1853 acquired additional territory from Mexico for the construction of a transcontinental railroad, completing the current southern border of the continental United States.

Expansionism and Manifest Destiny

The concept of Manifest Destiny played a crucial role in shaping American expansion during the mid-19th century. This ideology, coined by John O'Sullivan, promoted the belief that the United States had a divine right and duty to spread across the North American continent.

The Missouri Compromise of 1820 set the stage for future conflicts over slavery expansion. It established the 36°30' parallel as a dividing line between free and slave states, with slavery prohibited north of this line in the Louisiana Purchase territory.

Definition: Manifest Destiny was the belief that American expansion across the continent was both inevitable and divinely ordained.

President James K. Polk, a Democrat, strongly supported Manifest Destiny and sought to acquire Texas, Oregon, and California during his presidency. This expansionist agenda led to significant territorial gains but also increased tensions with Mexico.

Highlight: The California Gold Rush of 1849 accelerated westward migration and economic development in the newly acquired territories.

The Preemption Acts enabled Americans to purchase government land cheaply, encouraging settlement and farming in the western territories. This policy supported the goals of Manifest Destiny by facilitating rapid population growth in newly acquired lands.

Example: The battle cry "Remember the Alamo" emerged from the Texas Revolution against Mexico, becoming a symbol of American determination to expand westward.