Which U.S. President was in office during the Spanish-American War?

The President in office during the Spanish-American War was William McKinley. This conflict occurred in 1898 and was largely fueled by American imperialism and the desire to support Cuban independence from Spanish rule. McKinley's administration played a pivotal role in the decision-making that led to America's involvement in the war, including issues related to the explosion of the USS Maine in Havana harbor, which stirred public support for intervention.

Theodore Roosevelt, while an important figure during the war as he led the Rough Riders in the famous charge at San Juan Hill, was not the President at that time; he became President later after McKinley was assassinated in 1901. Woodrow Wilson, on the other hand, was President during World War I, which occurred years after the Spanish-American War. Franklin Pierce served as President much earlier, during the mid-19th century, well before the Spanish-American War took place. Thus, McKinley's leadership directly correlates with the events and decisions leading to the war and its execution.