During the late 1800s and the early 1900s, the US became much more involved in world affairs. In other words, they were becoming a world power. This meant many things, many changes.
In the 1880s, the US was still known as a minor county, a nation known to play only a small role in world affairs. Before the start of intervening in other nations, the US had followed a policy of isolationism, or having little to do with the political affairs of other nations. This was advised by George Washington in his Farewell Address and had been followed by later presidents. At the same time, however, the US also followed a policy of expansionism, or extending its national boundaries. An example of this was their constant westward movement across the continent. As all this was happening, the US was opening and increasing trade with countries across the world, especially those in Asia and the Pacific.
In the 1860s, William Seward, Secretary of State, wanted the US to dominate trade in the Pacific. In 1867, he succeeded in convincing Congress to annex Midway Island, an island in the middle of the Pacific Ocean. Seward also made a deal to buy Alaska, which belonged to Russia back then. The US gave up $7.2 million for this vast piece of land.
Between 1870 and 1914, imperialism, the policy of powerful countries seeking to control the economic and political affairs of weaker countries or regions began to occur in the US. Many European countries had been engaged in this practice for a long time, and the US finally decided to join in. The causes of this were Manifest Destiny, the need for more money and trade, and competition between the European countries for power and land. This eventually led the US deeper into the...