The United States emerged from the Civil War with new leverage in its negotiation with European countries, especially Great Britain, whose navy dominated the seas. Britain, which had allowed Confederate raiding ships such as CSS Alabama to be built in its shipyards, submitted afterward to arbitration and paid the United States $15.5 million in damages. Flush with victory, many Americans expected more British and Spanish territories to drop into the Union’s lap. Senator Charles Sumner proposed, in fact, that Britain settle the Alabama claims by handing over Canada.

Such dreams were a logical extension of pre–Civil War conquests, especially in the Mexican War. With the coasts now linked by rail, merchants and manufacturers looked across the Pacific, hungry for trade with Asia. Americans had already established a dominant presence in Hawaii, where U.S. whalers and merchant ships stopped for food and repairs. With the advent of steam-powered vessels, both the U.S. Navy and private shippers wanted more refueling points in the Caribbean and Pacific.

Even before the Civil War, these commercial aims had prompted the U.S. government to force Japan to open trade. For centuries, since unpleasant encounters with Portuguese traders in the 1600s, Japanese leaders had adhered to a policy of strict isolation. Americans, who wanted coal stations in Japan, argued that trade would extend what one missionary called “commerce, knowledge, and Christianity, with their multiplied blessings.” Whether or not Japan wanted these blessings was irrelevant. In 1854, Commodore Matthew Perry succeeded in getting Japanese officials to sign the Treaty of Kanagawa, allowing U.S. ships to refuel at two ports. By 1858, America and Japan had commenced trade, and a U.S. consul took up residence in Japan’s capital, Edo (now known as Tokyo).

Union victory also increased U.S. economic influence in Latin America. While the United States was preoccupied with its internal war, France had deposed Mexico’s government and installed an emperor. On May 5, 1867, Mexico overthrew the French invaders and executed Emperor Maximilian. But while Mexico regained independence, it lay open to the economic designs of its increasingly powerful northern neighbor.

A new model emerged for asserting U.S. power in Latin America and Asia: not by direct conquest, but through trade. The architect of this vision was William Seward, secretary of state from 1861 to 1869 under presidents Abraham Lincoln and Andrew Johnson. A New Yorker of grand ambition and ego, Seward believed, like many contemporaries, that Asia would become “the chief theatre of [world] events” and that commerce there was key to America’s prosperity. He urged the Senate to purchase sites in both the Pacific and the Caribbean for naval bases and refueling stations. When Japan changed policy and tried to close its ports to foreigners, Seward dispatched U.S. naval vessels to join those of Britain, France, and the Netherlands in reopening trade by force. At the same time, Seward urged annexation of Hawaii. He also predicted that the United States would one day claim the Philippines and build a Panama canal.

Seward’s short-term achievements were modest. Exhausted by civil war, Americans had little enthusiasm for further military exploits. Seward achieved only two significant victories. In 1868, he secured congressional approval for the Burlingame Treaty with China, which guaranteed the rights of U.S. missionaries in China and set official terms for the emigration of Chinese laborers, some of whom were already clearing farmland and building railroads in the West. That same year, Seward negotiated the purchase of Alaska from Russia. After the Senate approved the deal, Seward waxed poetic:

Our nation with united interests blest

Not now content to poise, shall sway the rest;

Abroad our empire shall no limits know,

But like the sea in endless circles flow.

Many Americans scoffed at the purchase of Alaska, a frigid arctic tract that skeptics nicknamed “Seward’s Icebox.” But the secretary of state mapped out a path his Republican successors would follow thirty years later in an aggressive bid for global power.