William McKinley (January 29, 1843 – September 14, 1901) was the 25th President of the United States, serving from March 4, 1897 until his assassination in September 1901. McKinley led the nation to victory in the Spanish–American War, raised protective tariffs to promote American industry, and maintained the nation on the gold standard in a rejection of inflationary proposals. Though McKinley's administration was cut short with his assassination, his presidency marked the beginning of a period of dominance by the Republican Party that lasted for more than a third of a century.
McKinley was the last President to have served in the American Civil War, beginning as a private in the Union Army and ending as a brevet major. After the war, he settled in Canton, Ohio, where he practiced law and married Ida Saxton. In 1876, he was elected to Congress, where he became the Republican Party's expert on the protective tariff, which he promised would bring prosperity. His 1890 McKinley Tariff was highly controversial; which together with a Democratic redistricting aimed at gerrymandering him out of office, led to his defeat in the Democratic landslide of 1890. He was elected Ohio's governor in 1891 and 1893, steering a moderate course between capital and labor interests. With the aid of his close adviser Mark Hanna, he secured the Republican nomination for president in 1896, amid a deep economic depression. He defeated his Democratic rival, William Jennings Bryan, after a front-porch campaign in which he advocated "sound money" (the gold standard unless altered by international agreement) and promised that high tariffs would restore prosperity.
Rapid economic growth marked McKinley's presidency. He promoted the 1897 Dingley Tariff to protect manufacturers and factory workers from foreign competition, and in 1900, he secured the passage of the Gold Standard Act. McKinley hoped to persuade Spain to grant independence to rebellious Cuba without conflict, but when negotiation failed, he led the nation in the Spanish–American War of 1898; the U.S. victory was quick and decisive. As part of the peace settlement Spain turned over to the United States its main overseas colonies of Puerto Rico, Guam, and the Philippines; Cuba was promised independence but at that time remained under the control of the U.S. Army. The United States annexed the independent Republic of Hawaii in 1898 and it became a U.S. territory.
McKinley defeated Bryan again in the 1900 presidential election, in a campaign focused on imperialism, prosperity, and free silver. President McKinley was assassinated by an anarchist in September 1901, and was succeeded by Vice President Theodore Roosevelt. Historians regard McKinley's 1896 victory as a realigning election, in which the political stalemate of the post-Civil War era gave way to the Republican-dominated Fourth Party System, which began with the Progressive Era. He is generally placed near the middle in rankings of American presidents.