American empire builders around 1900 fulfilled a vision laid out earlier by William Seward, secretary of state under presidents Abraham Lincoln and Andrew Johnson, who saw access to global markets as the key to power. Seward’s ideas had won only limited support at the time, but the severe economic depression of the 1890s brought Republicans into power and Seward’s ideas back into vogue. Confronting high unemployment and mass protests, policymakers feared American workers would embrace socialism or Marxism. The alternative, they believed, was to create jobs and prosperity at home by selling U.S. products in overseas markets.

Intellectual trends also favored imperialism. As early as 1885, in his popular book Our Country, Congregationalist minister Josiah Strong urged Protestants to proselytize overseas. He predicted that the American “Anglo-Saxon race,” which represented “the largest liberty, the purest Christianity, the highest civilization,” would “spread itself over the earth.” Such arguments were grounded in American exceptionalism, the idea that the United States had a unique destiny to foster democracy and civilization.

As Strong’s exhortation suggested, imperialists also drew on popular racial theories, which claimed that people of “Anglo-Saxon” descent — English and often German — were superior to all others. “Anglo-Saxon” rule over foreign people of color made sense in an era when, at home, most American Indians and Asian immigrants were denied citizenship and most southern blacks were disenfranchised. Imperialists argued that “free land” on the western frontier was dwindling, and thus new outlets needed to be found for American energy and enterprise. Responding to critics of U.S. occupation of the Philippines, Theodore Roosevelt scoffed: if Filipinos should control their own islands, he declared, then America was “morally bound to return Arizona to the Apaches.”

Imperialists also justified their views through racialized Social Darwinism. Josiah Strong, for example, predicted that with the globe fully occupied, a “competition of races” would ensue, with victory based on “survival of the fittest.” Fear of ruthless competition drove the United States, like European nations, to invest in the latest weapons. Policymakers saw that European powers were amassing steel-plated battleships and carving up Africa and Asia among themselves. In his book The Influence of Sea Power upon History (1890), U.S. naval officer Alfred Mahan urged the United States to enter the fray, observing that naval power had been essential to past empires. As early as 1886, Congress ordered construction of two steel-hulled battleships, the USS Texas and USS Maine; in 1890, it appropriated funds for three more, a program that expanded over the next two decades.

During Grover Cleveland’s second term (1893–1897), his secretary of state, Richard Olney, turned to direct confrontation. He warned Europe to stay away from Latin America, which he saw as the United States’s rightful sphere of influence. Without consulting the nation of Venezuela, Olney suddenly demanded in 1895 that Britain resolve a long-standing border dispute between Venezuela and Britain’s neighboring colony, British Guiana. Invoking the Monroe Doctrine, which stated that the Western Hemisphere was off-limits to further European colonization, Olney warned that the United States would brook no challenge to its interests. Startled, Britain agreed to arbitrate. U.S. power was on the rise.