The Mexican-American War, also known as the Mexican War, Mexican-American War, invasion of Mexico, American intervention, or the United States' War against Mexico, was an armed conflict between the United States and the Centralist Republic of Mexico from 1846 to 1848 following the 1845 American annexation of Texas, which Mexico considered part of its territory despite the Texas Riots of 1836. During this period, the supply ships from Texas San Blas remained unpredictable and the missions, with their native workers, were concerned with providing for the needs of the population. When indigenous groups began to resist larger demands, they were placed under stricter military control. Additionally, additional tribes were gathered, mixed, and grouped into dense groups in order to serve payment. Under these conditions, new diseases spread quickly and native crops were further disrupted. The continued damage caused by the Apaches and the failure of civil power to mount a determined response resulted in the abandonment of many smaller, more remote settlements. The population has become determined in central communities such as Tucson and Nogales. Additionally, continued civil unrest in central Mexico and the failure of the central government to establish effective functioning in the region resulted in the isolation of the southern Arizona population. Eventually, these issues caused a shift in the economic ties of people living on the border and united with the growing interests of the United States. With the opening of the Santa Fe Trail by Americans in 1821, the southwest region moved closer to land and sea directions that supplied communities along the Mississippi River as well as the western area of ​​the United States. Although the southern Arizona region ...... middle of paper ...... negotiate. In 1846 alone, the position was renewed four times, the war office six times, and the finance office sixteen times. But Mexican public opinion and all political groups agreed that selling the territories to the United States would ruin national honor. Mexicans in direct conflict with the United States, notably President José Joaquín de Herrera, were considered traitors. De Herrera's military opponents, supported by populist newspapers, considered Slidell's presence in Mexico City an insult. When de Herrera planned to receive Slidell to peacefully settle the Texas annexation issue, he was accused of treason and removed from office. After a more nationalist government led by General Mariano Paredes y Arrillaga came to power, he publicly reaffirmed Mexico's claim to Texas; Slidell, convinced that Mexico must be "punished", is sent back to the United States.