American Century

The American Century is a characterization of the period since the middle of the 20th century as being largely dominated by the United States in political, economic, technological, and cultural terms. It is comparable to the description of the period 1815–1914 as Britain's Imperial Century. The United States' influence grew throughout the 20th century, but became especially dominant after the end of World War II, when only two superpowers remained; the United States and the Soviet Union. After the dissolution of the Soviet Union in 1991, the United States remained the world's only superpower, and became the hegemon, or what some have termed a hyperpower.

The term was coined by Time publisher Henry Luce to describe what he thought the role of the United States would be and should be during the 20th century. Luce, the son of a missionary, in a February 17, 1941, Life magazine editorial urged the United States to forsake isolationism for a missionary's role, acting as the world's Good Samaritan and spreading democracy. He called upon the US to enter World War II to defend democratic values:

Throughout the 17th century and the 18th century and the 19th century, this continent teemed with manifold projects and magnificent purposes. Above them all and weaving them all together into the most exciting flag of all the world and of all history was the triumphal purpose of freedom.
It is in this spirit that all of us are called, each to his own measure of capacity, and each in the widest horizon of his vision, to create the first great American Century.

Democracy and other American ideals would "do their mysterious work of lifting the life of mankind from the level of the beasts to what the Psalmist called a little lower than the angels". Only under the American Century can the world "come to life in any nobility of health and vigor".

According to David Harvey, Luce believed "the power conferred was global and universal rather than territorially specific, so Luce preferred to talk of an American century rather than an empire". In the same article he called upon United States "to exert upon the world the full impact of our influence, for such purposes as we see fit and by such means as we see fit".

Beginning at the end of the 19th century, with the Spanish–American War in 1898 and the Boxer Rebellion, the United States began to play a more prominent role in the world beyond the North American continent. The government adopted protectionism after the Spanish–American War to develop its native industry and built up the navy, the "Great White Fleet". When Theodore Roosevelt became president in 1901, he accelerated a foreign policy shift away from isolationism and towards foreign involvement, a process which had begun under his predecessor William McKinley.

For instance, the United States fought the Philippine–American War against the First Philippine Republic to solidify its control over the newly acquired Philippines. In 1904, Roosevelt committed the United States to building the Panama Canal, creating the Panama Canal Zone. Interventionism found its formal articulation in the 1904 Roosevelt Corollary to the Monroe Doctrine, proclaiming a right for the United States to intervene anywhere in the Americas, a moment that underlined the emergent US regional hegemony.

After the outbreak of World War I in 1914, the United States pursued a policy of non-intervention, avoiding conflict while trying to broker a peace. President Woodrow Wilson later argued that the war was so important that the US had to have a voice in the peace conference. The United States was never formally a member of the Allies but entered the war in 1917 as a self-styled "Associated Power". Initially the United States had a small army, but, after the passage of the Selective Service Act, it drafted 2.8 million men, and, by summer 1918, was sending 10,000 fresh soldiers to France every day. The war ended in 1919 with the Treaty of Versailles. The United States then adopted a policy of isolationism, having refused to endorse the 1919 Versailles Treaty or formally enter the League of Nations.