Most Americans shared the concept of Manifest Destiny in the early to mid 1800’s. The idea created a sense of nationalism, which united the country even while sectionalism was growing stronger. Manifest Destiny played a major role in territory issues, legislative policies and president elections. All of these combined shaped the political structure for the next few decades to come.
Between 1820 and 1860 the U.S. almost doubled it’s size. Strong willed and stubborn presidents, such as Polk, greatly contributed to the expansion to the Pacific Coast. During his presidency he acquired three well-known territories. The Oregon territory was acquired from the Oregon controversy and California and Texas were acquired from the result of the Mexican War. The Oregon controversy refers to the northern boundary of Oregon, which Americans felt should be the 54 40’ line and the British felt should be the Columbia River (Doc. B). The Americans wanted more trade routes and protection of American interests in this region (Doc. F). Polk, hoping to avoid a clash with Britain, offered the 49th parallel as a compromise. Britain accepted and agreed to give the U.S. the land under the 49th parallel except Vancouver and the small islands around it. Texas had already declared its independence by the 1830’s and was an independent country. Polk attempted to acquire California from Mexico by offering to buy it. Mexico declined and the angered President Polk sent troops to the edge of the Rio Grande River. The Mexican-American War was fought from 1846-1848 and included many significant battles and key figures (Doc. C). The war ended with the Treaty of Guadalupe Hidalgo and its terms involved the confirmation of the American title to Texas, vast land in the west, and desirable California. The great expanse of land included in the Treaty of Guadalupe Hidalgo, which was about one-half of Mexico. The United States agreed to pay $15 million for the land and assume the claims against Mexico in...