USA HISTORY

Detailed explanation-1: -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-2: -The immediate cause of the Mexican-American War was a disputed boundary between the United States and Texas on the Nueces Strip.

Detailed explanation-3: -In the end, Texas was admitted to the United States a slave state. The annexation of Texas contributed to the coming of the Mexican-American War (1846-1848). The conflict started, in part, over a disagreement about which river was Mexico’s true northern border: the Nueces or the Rio Grande.

Detailed explanation-4: -Polk accomplished this through the annexation of Texas in 1845, the negotiation of the Oregon Treaty with Great Britain in 1846, and the conclusion of the Mexican-American War in 1848, which ended with the signing and ratification of the Treaty of Guadalupe-Hidalgo in 1848.

Detailed explanation-5: -Under the treaty, Mexico also recognized the U.S. annexation of Texas, and agreed to sell California and the rest of its territory north of the Rio Grande for $15 million plus the assumption of certain damage claims.