Western Expansion, Manifest Destiny, and the Mexican-American War

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How and why did the United States expand its territories?

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The U.S. expanded its territory largely through military conquest. Even purchases from other European powers, such as the Louisiana Purchase and Alaska, were done at the expense of indigenous people who already had a claim to the land.

Ideology fueled the conquest of much of the southern part of the North American continent. For example, in the first half of the nineteenth century, the United States embraced the idea of Manifest Destiny. This stated that it was obvious (manifest) that the United States was meant to own all the land below Canada between the the Atlantic and the Pacific oceans. According to this theory, God had long meant for the settlers of European descent to have this land. This ideology justified use of military force and the displacement of native peoples. It also instilled confidence that taking this land was possible and would lead to good outcomes,

Americans moved into these territories largely for economic opportunity—the chance to own farmland and the opportunity to use the continent's rich resources to become wealthy or at least comfortably independent. The new country offered economic possibilities not available to the average person in Europe, where the political and economic system had been established to benefit the aristocracy. The U.S. government gave away land in the west as "claims" in order to encourage settlement and legitimize U.S. ownership of these territories. Groups such as the Mormons also moved west seeking religious freedom.

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There were several examples of how the United States expanded its territories. Americans were willing to move into these territories for various reasons.

The first example of expansion came in 1803. We wanted to buy New Orleans and West Florida from France for $10 million. This would have helped western farmers with their trade since we, and not some other country, would control the port of New Orleans. The French countered our offer with a much better deal. They offered us the entire Louisiana Territory for $15 million. We made this purchase, doubling the size of our country.

Another area of expansion was the independent Republic of Texas. Texas wanted to join the United States immediately after becoming free from Mexican rule. However, a variety of issues, including the slavery issue, kept Texas from joining the country until 1845. In 1845, Texas joined the United States.

We were very interested in acquiring the Oregon Territory. It was shared between the United States and Great Britain. We reached a compromise with Great Britain. We got the southern part of the Oregon Territory while Great Britain got the northern part of it. This compromise added the Pacific Northwest region to our country.

We went to war with Mexico in 1846. This war, called the Mexican-American War, lasted from 1846-1848. As a result of the war, we got most of the southwest part of what is now the United States.

There were a few land purchases that added to our country. In 1853, as a result of the Gadsden Purchase, we added the southern part of both New Mexico and Arizona to our country. We paid Mexico $10 million for this land. In 1867, we bought Alaska from Russia for $7.2 million.

The United States got some land through our policy of imperialism in the 1890s and 1900s. We eventually got control in Hawaii after a revolution against the Queen. We annexed Hawaii in 1898. We added land as a result of the Spanish-American War. We got Guam, Puerto Rico, and the Philippines for $20 million. We still control Guam and Puerto Rico.

Americans moved to the new lands we got, especially the areas that makes up the lower 48 states, for a variety of reasons. Some people wanted to get land, and there was plenty available. Others went for a spirit of adventure. There was a lot of excitement in moving to a new place. Many people went for economic opportunities. People hoped to make a lot of money by discovering minerals in the West. Others went to farm the land or to raise cattle and sheep. Businesses saw opportunities for growth in the West once people moved there. Thus, businesses followed the people who moved to the West.

Throughout our history, we have been growing as a nation. Our people have been more than willing to go to the new territories after we got possession of them.

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