In South America, there are many corrupt governments and violent gangs. The governments were put there by the Soviets or Americans. It was the Cold War (which was about influence) and so they put many governments in charge. This lead to mass immigration to the U.S were life was easier and Texas just so happened to have the largest border with Mexico than any other state.
The Act Prohibiting Importation of Slaves of 1807 (2 Stat. 426, enacted March 2, 1807) is a United States federal law that stated that no new slaves were permitted to be imported into the United States. It took effect in 1808, the earliest date permitted by the United States Constitution.