The Treaty of Guadalupe Hidalgo

With a signed treaty and 15 million dollars, the U.S. added territory that would eventually become California and Texas, and parts of Arizona, Colorado, Nevada, New Mexico, and Utah. (With the Gadsden Purchase in 1853, the U.S. added the southern-most parts of Arizona and New Mexico for 10 million dollars.)

Article VIII of the treaty guaranteed protection for the property and civil rights of Mexican citizens who chose to stay in the now U.S.-governed land. Over time, Mexicans who remained discovered that the U.S. Government would not strictly enforce the protection of their property rights.