It wasn't long after the United States obtained these new lands that thousands of Chicanos lost their homeland. These indigenous citizens had already acquired ownership of their property through Spanish or Mexican laws. However, because American courts did not recognize these laws, these natives were stripped of their land. According to a prominent Chicano activist, Reyes López Tijerina, the United States illegally confiscated these citizens' lands. Tijerina discusses the fact that after the Mexican-American War, the United States and Mexico signed the Treaty of Guadalupe Hidalgo, which promised these natives free use of their properties. However, by depriving these indigenous people of their land, the United States is going against the promise it made in the Treaty of Guadalupe Hidalgo, to allow the indigenous people to enjoy their land or property. By going against this treaty, the United States is going against its own laws, because due to the Constitution of the United States, Article Twelve, Section Two, which states that all treaties created by the United States is the supreme law, the Treaty of Guadalupe Hidalgo is a law1. Another example of why some land was illegally seized was the signing of the Tierra Maria grant. This concession made it possible to sell a large quantity of land belonging to numerous heirs.