Under the treaty that ended the Mexican War, most of the Mexicans who lived in the new United States territories became U.S. citizens. The treaty also guaranteed their safety and property rights, "as if the [property] belonged to citizens of the U.S. according to the principles of the Constitution." In practice, however, the new territories were far from the centers of U.S. government, and these guarantees were not reliably enforced. By the end of the 19th century, many Mexican Americans had been deprived of their land, and found themselves living unprotected in an often hostile region.
