Theodore Roosevelt Campaign Button, 1900

Theodore Roosevelt's leadership of the Rough Riders during the Spanish-American War became a major campaigning tactic for the 1900 McKinley-Roosevelt presidential campaign. The decision to add Roosevelt as a running mate helped the two candidates score a decisive victory over Democratic challenger William Jennings Bryan. On September 14, 1901, McKinley died from an assassin's bullet, thrusting Roosevelt into the presidency.