Final answer:
President William McKinley sent the USS Maine to Cuba to protect American interests, leading to a pivotal series of events that contributed to the Spanish-American War.
Step-by-step explanation:
It was President William McKinley who sent the American battleship, the USS Maine, to Cuba to protect American lives and interests. In January of 1898, concerned about the instability in Cuba and the potential threat to American citizens and economic interests, particularly in the sugar industry, President McKinley dispatched the USS Maine to Havana Harbor, with Spain's permission. The explosion of the USS Maine on February 15, 1898, which killed over 250 sailors, was a pivotal event that led to the outbreak of the Spanish-American War, following the intense public outcry and sensationalism by the press, despite later investigations suggesting the explosion was an internal accident.