USA HISTORY

Detailed explanation-1: -In January 1846 Polk ordered General Zachary Taylor to occupy disputed borderlands between the Nueces and Rio Grande rivers. (Texas claimed that its southwest boundary extended to the Rio Grande. Mexico claimed that the boundary was the Nueces, 100 miles [160 kilometers] eastward.)

Detailed explanation-2: -Mexican Pres. José Joaquín Herrera, aware in advance of Slidell’s intention of dismembering the country, refused to receive him. When Polk learned of the snub, he ordered troops under Gen. Zachary Taylor to occupy the disputed area between the Nueces and the Rio Grande (January 1846).

Detailed explanation-3: -In July of 1845, Polk ordered General Zachary Taylor to cross the Nueces River with his command of 4, 000 troops. Upon learning of Slidell’s rejection, Polk sent word that Taylor should advance his troops to the Rio Grande River. From the standpoint of Mexico, the United States had invaded their territory.

Detailed explanation-4: -Polk ordered General Zachary Taylor to move a force into Texas to defend the Rio Grande border.

Detailed explanation-5: -In the 1830s, the Republic of Texas claimed the Rio Grande as its southern border; Mexico claimed the Nueces River (150 mi or 240 km north of the Rio Grande). The area between the two rivers became known as the Nueces Strip. Both countries invaded it, but neither controlled it nor settled it.