James K. Polk
What war did Polk wage that led to greater territory for the United States?
Fulfilling the Democrat phrase “manifest destiny,” Polk engaged the United States in the Mexican-American War that led to the eventual annexation of California. Tensions were already hot between the two countries after the annexation of Texas, which had begun in earnest at the end of the Tyler administration, but was completed officially in Polk’s term.
But Polk wanted more for the country—the provinces of New Mexico and California. Mexican troops had crossed the Rio Grande and killed American soldiers in the dispute. Polk sent Zachary Taylor—his presidential successor—into the region. Taylor achieved several victories over the Mexican army at Palo Alto and Resaca de la Palma. Taylor later defeated Mexican forces at Buena Vista in 1847. American armies led by either Taylor or General Winfield Scott actually took Mexico City during the conflict.
After the United States conquered Mexico City, Mexico realized that it had better sell its land in New Mexico and California and end the war. Some speculated that the United States should simply take control of all of Mexico. This was known as the “All Mexico” campaign. Polk faced resistance to the war from many in the country, and decided to obtain peace and enlarge the country with more than a half a million square miles.