William McKinley was the 25th Predsident of the United States. His assassination occurred on September 6, 1901, inside the Temple of Music located on the grounds of the 1901 Pan-American Exposition in Buffalo, New York. He is best known for winning intensely-fought elections by fighting for gold. He is also known for leading the nation to victory in 90 days in the Spanish American War, and for forging a Republican.By the 1880s, McKinley was a national Republican leader; his signature issue was high tariffs on imports as a formula for prosperity, as typified by his McKinley Tariff of 1890. As the Republican candidate in the 1896 presidential election, against Democrat William Jennings Bryan, he upheld the gold standard, and promoted pluralism among ethnic groups. His campaign, designed by Mark Hanna, introduced new advertising-style campaign techniques that revolutionized campaign practices and beat back the crusading of his arch-rival, William Jennings Bryan.

McKinley presided over a return to prosperity after the Panic of 1893, and made gold the base of the currency. He demanded that Spain end its atrocities in Cuba, which were outraging public opinion; Spain resisted the interference and the Spanish-American War became inevitable in 1898. The war was fast and easy, as the weak Spanish fleets were sunk and both Cuba and the Philippines were captured in 90 days. As a result of the 1898 Treaty of Paris, the former Spanish colonies of Puerto Rico, Guam, and the Philippines were annexed by the United States as unincorporated territories, and Cuba was subjected to United States occupation. Although support for the war itself was widespread, the Democrats and anti-imperialists vehemently opposed the annexation of the Philippines, fearing a loss of republican values. McKinley also annexed the independent Republic of Hawaii in 1898, with all its residents becoming full American citizens. McKinley was reelected in the 1900 presidential election following another intense campaign against Bryan, which focused on foreign policy and the return of prosperity. McKinley was assassinated by anarchist Leon Czolgosz, in 1901, and succeeded by his Vice President Theodore Roosevelt.

As he was visiting the Exposition and was in a receiving a line of shaking hands with ordinary citizens, he was shot twice by Leon Czolgosz, an anarchist. McKinley initially appeared to be recovering from his wounds, but took a turn for the worse six days after the shooting and died on September 14, 1901. McKinley was the third of the four U.S. presidents to be assassinated, following Abraham Lincoln in 1865 and James A. Garfield in 1881 and preceding John F. Kennedy in 1963. After McKinley's murder, Congress officially charged the Secret Service with the physical protection of U.S. presidents.