III.

U.S. Policy Prior to World War II

Throughout much of the 19th and early 20th centuries, the United States followed a course of political isolationism, even as it extended its commercial relationships worldwide. This political isolationism did not apply to the country’s domestic efforts to expand its territory on its own continent. Such efforts were associated with Manifest Destiny, the belief that U.S. expansion was not only inevitable but also a divine right. For example, in 1803 the United States bought a vast region of territory in North America from France in a deal known as the Louisiana Purchase. During the 1800s the United States also purchased Alaska from Russia, and Texas and other territories from Mexico.

Throughout the 19th century, however, the United States resisted entering into foreign conflicts. Protecting domestic interests alone was not a good enough reason to become involved. Some higher moral principle had to be at stake. For example, the United States fought the War of 1812 against Britain in Canada and at home to stop the British from blockading international waters. In 1898 the United States fought the Spanish-American War to liberate Cuba from Spanish rule. The United States did not enter World War I (1914-1918) until Germany violated international law in 1917 by resuming its campaign of unrestricted submarine warfare.

After World War I, the United States reverted back to isolationism. As a result, the United States did not join the League of Nations when it was founded in 1920 or during the 26 years of its existence.