From the National Constitution Center:
On August 12, 1898, the United States and Spain reached a cease-fire agreement in its brief conflict over Cuba and the Philippines. The war marked America’s entrance onto the global stage as a military power.
The Spanish-American War is just one of five conflicts where Congress approved an official declaration of war using its constitutional powers. In total, war declarations have been declared by Congress in the War of 1812, the Mexican-American War, the Spanish-American War, World War I and World War II.
The dispute between the two nations over Cuba had been simmering for decades. Earlier in the 19th Century, American forces landed on Cuban soil on several occasions to pursue pirates, and then the United States’ government tried to buy Cuba from Spain.
Prior to the war declaration by Congress on April 25, 1898, tensions were high as United States business interests eyed the sugar-producing industry in Cuba. The island had been ravaged by three years of civil war, which had been highly dramatized in some American newspapers.
And after the sinking of the battleship Maine in Havana’s harbor on February 15, war seemed inevitable. The Maine had been sent to Cuba by President William McKinley to safeguard American interests. On March 9, 1898 Congress passed a law to build up the United States’ military strength. On March 28, 1898 an investigation found that a mine blew up the Maine.
On April 21 President McKinley orders a blockade of Cuba, leading to Spain breaking off diplomatic relations, and four days later the U.S. Congress declared war on Spain, two days after Spain issued its own war declaration.
The actual fighting in the declared war lasted for a 10-week period. On May 1, in Manila Bay, Commodore George Dewey’s Asiatic Squadron defeated the Spanish naval force located in the Philippines, another Spanish possession. In June, American troops captured Guantanamo Bay in Cuba and attacked the harbor city of Santiago. After defeating the Spanish army on the ground in Cuba, the U.S. used its Navy to destroy the Spanish Caribbean squadron in July.
By late July, France intervened for Spain to start peace negotiations, and a cease-fire was signed on August 12. The final peace between U.S. and Spanish governments came with the Treaty of Paris on December 10, 1898.
The costs to Spain were heavy. It had to guarantee the independence of Cuba, give Guam and Puerto Rico to the United States, and agree to sell the Philippines to the United States for the sum of $20 million.
For the United States, the monetary cast was $250 million for the war. About 3,000 troops died in the conflict, with an estimated 90 percent dying from diseases.
But there was one final constitutional step in the process: the U.S. Senate had to ratify the treaty in February 1899, and that was far from guaranteed.
A two-thirds majority of the Senate is needed to approve a treaty, and a powerful anti-Imperialist group opposed expanding the United States into a global power. The lobby included former Presidents Benjamin Harrison and Grover Cleveland, and industrialist Andrew Carnegie.
The U.S. Senate ratified the treaty on February 6, 1899, by a margin of just one vote, after William Jennings Bryan decided to support a treaty backed by his arch rival, President McKinley.
Also, during the conflict, the United States annexed Hawaii. A joint resolution of Congress made Hawaii a U.S. territory on August 12, 1898, as concerns grew about its strategic importance in protecting the prospective new American interests in the Pacific. The United States also purchased a perpetual lease on Guantanamo Bay in Cuba in the war’s aftermath.