Why did McKinley win the Nobel Peace Prize?

William McKinley did not win the Nobel Peace Prize; in fact, he was assassinated in 1901 before the prize was established in 1901. The first recipient of the Nobel Peace Prize was Henry Dunant, co-founder of the International Committee of the Red Cross, in 1901. McKinley is often remembered for his role in the Spanish-American War and for promoting U.S. Imperialism, rather than for peace efforts.