Westward expansion and manifest destiny had a very negative effect on the Mexicans and on the Native Americans. As Americans wanted to expand westward, they continued to view the Native Americans as being in the way and holding back the progress of our country. In the 1830s, the Native Americans were forcibly removed from their lands east of the Mississippi River to lands west of the Mississippi River. Many Native Americans died as a result of the forced relocation, which often is referred to as the Trail of Tears. As Americans began to expand beyond the Mississippi River, Americans again viewed the Native Americans as holding back the progress of our country. New policies were developed placing Native Americans on reservations. These policies disrupted and, in some cases, destroyed their way of life. These policies were made with the interests of the Americans in mind, not with the interests of the Native Americans in mind. Westward expansion and manifest destiny were not positive events for the Native Americans.
Mexicans were also negatively impacted by these policies. We wanted to gain control of the lands Mexico controlled in the southwest. As a result of a border dispute we had with Mexico regarding the border of Texas, we went to war against Mexico in 1846. As a result of winning this war, known as the Mexican-American War, we got the lands that today make up the southwest part of our country. We also established the Rio Grande River as the border between Texas and Mexico. Westward expansion and manifest destiny negatively impacted the Mexicans.
Both the Native Americans and the Mexicans were impacted by these concepts in another way. As Americans moved westward, they brought diseases with them to which the Native Americans and the Mexicans had no immunity. Many Native Americans and Mexicans contracted these diseases and died from them.
Both westward expansion and manifest destiny were very detrimental to the Mexicans and the Native Americans.