One of the causes of the Civil War was the question of whether to establish slavery in the west. The debate between the government has intensified as whether slavery should be allowed in the new territories taken from Mexico after the Mexican-American War (Corbett, et al, 421). From 1790 to 1860, the number of the salves in the United States has increased to 4 million from 500,000 (Howard, 171). The North advocated to develop capitalism, limit and even ban the expansion of the slavery in the west, on the contrary, the South upheld the expansion of the slavery in the west and the nation. The Congress presented the principle of popular sovereignty, letting people in the new territories to decide this issue, which added fuel to the fire of sectional conflict (Corbett, et al, 421).
Second, the overwhelming abolitionist movement launched by the North has led to the increasing tensions between the North and the South. Some …show more content…
On the one hand, the United Stated argued that the Rio Grande was the border between Mexico and the United States, however, on the other hand, the Mexico disagreed this statement and insisted the border lay farther north, at the Nueces River (Corbett, et al, 315). The Americans intended to take advantage of the indistinct border issue to manipulate the land they never occupied. The Texas wanted to be independent and initialed the Texas war. While the Mexico refused to recognize its independence and rejected its statement to make the Rio Grande as its border with the Mexicor (Corbett, et al, 315). In 1845, the Texas agreed to be one state of the United States for its claiming to admit the Rio Grande as the Texas’ border if it willing to join the United States. The Mexican government was very angry about that because the United State involved in its internal