USA HISTORY

Detailed explanation-1: -The U.S. sent troops to the disputed Rio Grande, ignoring Mexican demands to withdraw. Mexico subsequently attacked a group of 80 soldiers on April 25, 1846, a move which Polk used to convince the Congress of the United States to declare war.

Detailed explanation-2: -Polk grew frustrated. Determined to acquire the land, he sent American troops to Texas in January of 1846 to provoke the Mexicans into war. When the Mexicans fired on American troops in April 25, 1846, Polk had the excuse he needed.

Detailed explanation-3: -On May 12, 1846, the United States Senate voted 40 to 2 to go to war with Mexico. President James K. Polk had accused Mexican troops of having attacked Americans on U.S. soil, north of the Rio Grande.

Detailed explanation-4: -It stemmed from the annexation of the Republic of Texas by the U.S. in 1845 and from a dispute over whether Texas ended at the Nueces River (the Mexican claim) or the Rio Grande (the U.S. claim).

Detailed explanation-5: -Among those opposed to the war with Mexico was the newly elected congressman Abraham Lincoln. Author Henry David Thoreau refused to pay taxes that would support the war and was subsequently jailed, where he wrote his essay Civil Disobedience.