United States History Student Edition

refused to sell the lands, Polk planned to gain them through war. U.S. War Plans To justify a war, President Polk tried to get Mexico to strike first. He ordered General Zachary Taylor to lead U.S. forces across the Nueces River into the disputed area. To Mexican leaders, Taylor’s action was an invasion of their country. On April 25, 1846, Mexican troops attacked Taylor’s forces. President Polk told Congress that Mexico had “invaded our territory and shed American blood upon the American soil.” On May 13, Congress passed a declaration of war against Mexico. In his subsequent speeches, Polk admitted that the Mexican attack had occurred in disputed territory. The Whig-controlled House voted to censure, or reprimand, the president, but the war was already underway. Polk planned to defeat Mexico by accomplishing three goals. First, the United States would drive Mexican forces out of Texas. Second, it would seize New Mexico and California.

7 CHECK FOR UNDERSTANDING Making Connections Why did it take nine years for the United States to annex Texas? Conflict With Mexico GUIDING QUESTION Why did war break out between the United States and Mexico? Relations between Mexico and the United States had not been friendly since Texas annexation. A main point of disagreement was the location of the Texas-Mexico border. The United States said that the Rio Grande formed the border. Mexico claimed that the border lay along the Nueces (nu•AY•sehs) River, 150 miles (241 km) farther north. President James K. Polk sent a representative, John Slidell, to Mexico to propose a deal. Slidell offered $30 million for California and New Mexico if Mexico would accept the Rio Grande as the border between Texas and Mexico. Mexican leaders refused to discuss the offer. They announced that they intended to reclaim Texas for Mexico. Polk was determined to get the California and New Mexico territories from Mexico. After Mexico

justify to prove or show to be right

War With Mexico, 1846–1848 War between the United States and Mexico broke out in 1846 near the Rio Grande. Polk’s party, the Democrats, generally supported the war. Many Whigs did not, calling Polk’s actions unnecessary and unjust. Northerners accused Democrats of waging war to gain territory for the spread of slavery.

GEOGRAPHY CONNECTION 1. Exploring Place Which battle was a Mexican victory? 2. Patterns and Movement What information on the map can you use to infer which side won the war?

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Polk, James K. “Polk’s Mexican War Message.” Williams, Edwin, comp. The Addresses and Messages of the Presidents of the United States, Inaugural, Annual, and Special, from 1780 to 1854. Vol. 3. New York: Edward Walker, 1854.

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