TEXAS AND WAR WITH MEXICO
Throughout the 1820s, Ameri- cans settled in the vast territory of Texas, often with land grants from the Mexican government . However, their numbers soon alarmed the au- thorities, who prohibited further im- migration in 1830 . In 1834 General Antonio López de Santa Anna estab- lished a dictatorship in Mexico, and the following year Texans revolted . Santa Anna defeated the American rebels at the celebrated siege of the Alamo in early 1836, but Texans under Sam Houston destroyed the Mexican Army and captured Santa Anna a month later at the Battle of San Jacinto, ensuring Texan inde- pendence .
For almost a decade, Texas re- mained an independent republic, largely because its annexation as a huge new slave state would disrupt the increasingly precarious balance of political power in the United States . In 1845, President James K . Polk, narrowly elected on a platform of westward expansion, brought the Republic of Texas into the Union . Polk’s move was the first gambit in a larger design . Texas claimed that
CHAPTER 6: SECTIONAL CONFLICT
OUTLINE OF U.S. HISTORY
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its border with Mexico was the Rio Grande; Mexico argued that the border stood far to the north along the Nueces River . Meanwhile, set- tlers were flooding into the territo- ries of New Mexico and California . Many Americans claimed that the United States had a “manifest des- tiny” to expand westward to the Pa- cific Ocean .
U .S . attempts to purchase from Mexico the New Mexico and Cali- fornia territories failed . In 1846, after a clash of Mexican and U .S . troops along the Rio Grande, the United States declared war . Ameri- can troops occupied the lightly populated territory of New Mexico, then supported a revolt of settlers in California . A U .S . force under Zachary Taylor invaded Mexico, winning victories at Monterrey and Buena Vista, but failing to bring the Mexicans to the negotiating table . In March 1847, a U .S . Army command- ed by Winfield Scott landed near Veracruz on Mexico’s east coast, and fought its way to Mexico City . The United States dictated the Trea- ty of Guadalupe Hidalgo in which Mexico ceded what would become the American Southwest region and California for $15 million .
The war was a training ground for American officers who would later fight on both sides in the Civil War . It was also politically divisive . Polk, in a simultaneous facedown with Great Britain, had achieved British recognition of American sov- ereignty in the Pacific Northwest to the 49th parallel . Still, antislavery
forces, mainly among the Whigs, at- tacked Polk’s expansion as a proslav- ery plot .
With the conclusion of the Mexi- can War, the United States gained a vast new territory of 1 .36 million square kilometers encompassing the present-day states of New Mexico, Nevada, California, Utah, most of Arizona, and portions of Colorado and Wyoming . The nation also faced a revival of the most explosive ques- tion in American politics of the time: Would the new territories be slave or free?