According to Franklin K.Van Zandt, U.S Geological survey professional paper 909, boundaries of the united states and several states (p. 2), the original territory of the United states was defined by the treaties of November 30th, 1782 and September 3rd, 1783 with great Britain bounded on the north by Canada, on the south by Spanish colonies of East and west Florida, on the East by Atlantic ocean and on the West by Mississippi river. However, he noted that America was keen to have its boundaries expanded. This paper therefore attempts to look at the possible causes, impacts, political take and consequences of territorial expansion especially on slavery.

Most importantly, the War of 1812 the United State of America emerged the superpower. This was due to acquisitions to events such as Louisiana Purchase, Mexican cession and the addition of cities such as Alaska, Florida, Texas and Oregon; this tripled its size from its original in less than 100 years. This war was mainly caused by United Kingdom’s meddling on the U.S affairs by blocking its ships from going to France. After successful resistance to Britain during the war, the United States gained an international respect, strengthened its army, attained economic power through its manufactured import goods.

Secondly, the 1846 Manifest Destiny extended America’s destiny from Atlantic to Pacific Ocean as was determined by the war- a phenomenon that kept the US military more organized and united throughout the war. “Americans not only had massive feelings of Nationalism and economic power after the war but were also focused on expanding their dominion beyond the Pacific Ocean” (Zandt & Morehouse, p. 123). Consequently, Annexation of Texas followed under the influence of the Southerners amidst opposition of the Northerners on the basis that the move would politically strengthen slave power and further initiate war with Mexico. The South won after Texas annexation was approved and signed into law by President Taylor at Washington DC (Sonneborn, p. 9).

Subsequently, Mexican-American War sparked erupted when Texas got its independence from Mexico in 1836. During the war, Mexican General Antonio Lopez was captured and forced into recognizing the independence of Texas in return for freedom, but the Mexican Government declined thus the beginning of the war. Texas then received diplomatic recognition from United States, France and Great Britain (Sonneborn, p. 11). Focusing on the Manifest Destiny, The British had earlier rejected the treaty allowing joint occupation of the Oregon country, which would have made Washington part of British North America. However, Oregon treaty was signed in 1846, which both party agreed, since America was about to start war with Mexico as explained by Emmanuel Leutze in his publication “The history of Mexican American war.”

Consequences of Mexico-America war

Meanwhile there was a brewing Filibustering in the south. After the end of Mexico-America war in 1848, disagreements over the expansion of slavery made further territorial annexation too disruptive to be official Government policy. Many northerners opposed what they believed were a plot to expand slavery in America against the spirits of U.S Emancipation Act. This led to military filibustering that almost later led to the American Civil War from 1861 – 1865 (Sonneborn, p. 13).

Finally, the Missouri compromise, an agreement passed in 1820 between the pro -slavery and the anti -slavery factions in the United States congress involving regulation of slavery in the western territories, helped guard the Southern and Northern states against possible split. Although each side was relieved by the compromise, they dissented some specific provisions. Among the beneficiaries was California which became Free State in the union instead of being split (Sonneborn, p. 16).

In conclusion, the United States of America expanded its boundaries in the 18th Century by employing its military and economic power to subdue neighboring cities such as Alaska, Florida, North Carolina, Texas and Oregon that were originally occupied by the Native American and other colonial powers such as Spain and Great Britain. The sharp division between the slave Southern states and the free northern states later led to the American Civil War that began in 1861.

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