How many Americans today know about the Spanish–American War of 1898?
The late 1890s saw widespread anti-Spanish propaganda and yellow journalism, led by Joseph Pulitzer of the New York World and William Randolph Hearst of the New York Journal. Many Americans saw Spain as a classic oppressor in Cuba, and viewed the struggle for Cuban independence as a parallel of their own, one century earlier.
The United States also had deep financial investments in Cuba, and annual trade (primarily in sugar) was over $100 million. And while President Grover Cleveland declared neutrality in 1895, by 1898 the national climate had shifted. On February 15th, a mysterious explosion sank the U.S.S. Maine in Havana Harbor and 266 American sailors were killed. The U.S. Navy declared that a mine destroyed the Maine; President McKinley ordered a blockade of Cuba, and on April 25th the U.S. declared war.
The US Army was still severely weakened following the Civil War, and President McKinley called for volunteers to aid in the war efforts. The 1st United States Volunteer Cavalry was the only one of three volunteer regiments to see action; they are far more recognizable by their other name – the Rough Riders, led by Theodore Roosevelt. (Roosevelt resigned his position of Assistant Secretary of the Navy to join the volunteer cavalry, to great acclaim.)
After fierce fighting, Spain and the United States signed a peace treaty on December 10, 1898. The Treaty of Paris, negotiated on terms favorable to the U.S., allowed temporary American control of Cuba, and ceded authority over Puerto Rico, Guam and the Philippine islands from Spain.
The war had cost the United States $250 million and 3,000 lives, of whom 90% had perished from infectious diseases. Both the preparations for the war and its aftermath took a harsh toll on many of the volunteers; here you can see Theodore Roosevelt describing the suffering of the Rough Riders, weeks after the crucial Battle of San Juan Hill.