History of Mexican American and its influence on Future There has been a long history of conflict, migration, intermarriages, and inter-cultural connections between Americans and Mexicans. According to the Mexican American war that started on April 25, 1846, in the Rio Grande increased the American states while reducing Mexican lands. Under President Polk, the United States wanted to expand to Southwest. The Mexican that lived in regions like California, New Mexico, and Oregon became American citizens after the annexation of the Mexican territory. Since then, Mexican Americans have merged in .U.S. and specifically in regions of California, Nevada, Arizona, and Texas. In the past Century, American Americans have engaged in active campaigns and fights with the U.S. government about voting