how did mexico lose land to america?

The treaty established the Texas-Mexican border along the Rio Grande; fifteen years later it would be the same river that led to the Chamizal dispute between Mexico and the United States. Instead, they resorted to renting horses from campaign to campaign, rather than pay for their continual upkeep. From 1821 to 1822 Mexico annexed those territories, which were other former Spanish colonies that also revolted from Spain. // -->