USA HISTORY

Detailed explanation-1: -The Mexican-American War was the first major conflict driven by the idea of “Manifest Destiny"; the belief that America had a God-given right, or destiny, to expand the country’s borders from ‘sea to shining sea’.

Detailed explanation-2: -It pitted a politically divided and militarily unprepared Mexico against the expansionist-minded administration of U.S. President James K. Polk, who believed the United States had a “Manifest Destiny” to spread across the continent to the Pacific Ocean.

Detailed explanation-3: -In 1845 the United States annexed Texas and subsequently engaged in a dispute with Mexico over the southern Texas-Mexico border. Texas claimed that its southwest boundary extended to the Rio Grande. Mexico claimed that the boundary was the Nueces River, which is 100 miles (160 kilometers) eastward.

Detailed explanation-4: -Under the terms of the treaty negotiated by Trist, Mexico ceded to the United States Upper California and New Mexico. This was known as the Mexican Cession and included present-day Arizona and New Mexico and parts of Utah, Nevada, and Colorado (see Article V of the treaty).