The relations between the two countries, however hostile, continued until 1845 after the annexation of Texas by the United States, and the beginning of the Mexican–American War.

[3] In 1829, U.S. President Andrew Jackson made a failed attempt to buy Texas from Mexico (for $5 million).

When the government began to enforce the ban on slavery, desire for secession reached its peak, eventually leading to the Texas Revolution, and de facto Texan Independence.

By 1838, though Texas consolidated a firm hold over its eastern lands, a majority of territory claimed under the Treaty of Velasco remained under either Indian hegemony or Mexican control.

Texas claimed the official southern and western border between the two countries to be the Rio Grande, Mexico considered it a ridiculous compromise to even allow the eastern part of Texas to remain independent while insisting any border that may exist was at the Nueces.