With the Cuban insurgents on the verge of victory, President William McKinley came to favor military intervention as a way to increase U.S. control of postwar Cuba. By intervening before the Cubans won on their own, the United States staked its claim for determining the postwar relationship between the two countries and protecting its vital interests in the Caribbean, including the private property rights of U.S. landowners in Cuba.

The U.S. press, however, helped build support for U.S. intervention not by focusing on economic interests and geopolitics but by framing the war as a matter of U.S. honor. William Randolph Hearst’s New York Journal competed with Joseph Pulitzer’s New York World to see which could provide the most lurid coverage of Spanish atrocities. Known disparagingly as yellow journalism, these sensationalist newspaper accounts aroused jingoistic outrage against Spain.

On February 15, 1898, the battleship Maine, anchored in Havana harbor, exploded, killing 266 U.S. sailors. Newspapers in the United States blamed Spain. The World shouted the rallying cry “Remember the Maine! To hell with Spain!” Assistant Secretary of the Navy Theodore Roosevelt seconded this sentiment by denouncing the explosion as a Spanish “act of treachery.” Why the Spaniards would choose to blow up the Maine and provoke war with the United States while already losing to Cuba remained unanswered, but the incident was enough to turn U.S. opinion toward war.

On April 11, 1898, McKinley asked Congress to declare war against Spain. The declaration included an amendment proposed by Senator Henry M. Teller of Colorado declaring that Cuba “ought to be free and independent.” Yet the document left enough room for U.S. maneuvering to satisfy the imperial ambitions of the McKinley administration. In endorsing independence, the war proclamation asserted the right of the United States to remain involved in Cuban affairs until it had achieved “pacification.” On April 21, the United States officially went to war with Spain.

In going to war, McKinley embarked on an imperialistic course that had been building since the early 1890s. The president signaled the broader expansionist concerns behind the war when, shortly after it began, he successfully steered a Hawaiian annexation treaty through Congress. Businessmen joined imperialists in seizing the moment to create a commercial empire that would catch up to their European rivals.

It was fortunate for the United States that the Cuban insurgents had seriously weakened Spanish forces before the U.S. fighters arrived. The U.S. army lacked sufficient strength to conquer Cuba on its own, and McKinley had to mobilize some 200,000 National Guard troops and assorted volunteers. Theodore Roosevelt resigned from his post as assistant secretary of the navy and organized his own regiment, called “Rough Riders.” U.S. forces faced several problems: They lacked battle experience; supplies were inadequate; their uniforms were not suited for the hot, humid climate of a Cuban summer; and the soldiers did not have immunity from tropical diseases.

African American soldiers, who made up about one-quarter of the troops, encountered additional difficulties. As more and more black troops arrived in southern ports for deployment to Cuba, they faced increasingly hostile crowds, angered at the presence of armed African American men in uniform. In Tampa, Florida, where troops gathered from all over the country to be transported to Cuba, racial tensions exploded on the afternoon of June 8. Intoxicated white soldiers from Ohio grabbed a two-year-old black boy from his mother and used him for target practice, shooting a bullet through his shirtsleeve. In retaliation, African American soldiers stormed into the streets and exchanged gunfire with whites, leaving three whites and twenty-seven black soldiers wounded.

Despite military inexperience, logistical problems, and racial tensions, the United States quickly defeated the weakened Spanish military, and the war was over four months after it began. During this war, 460 U.S. soldiers died in combat, far fewer than the more than 5,000 who lost their lives to disease. The subsequent peace treaty ended Spanish rule in Cuba, ceded Puerto Rico and the Pacific island of Guam to the United States, and recognized U.S. occupation of the Philippines until the two countries could arrange a final settlement. As a result of the territorial gains in the war, U.S. foreign-policy strategists could now begin to construct the empire that Mahan had envisioned.