William McKinley was the 25th president of the United States. In 1901 he was shot by Leon Czolgosz, an unemployed anarchist, at the Pan-American Exposition in Buffalo. One bullet ricocheted off a button on the president's vest, but a second pierced his abdomen. McKinley died eight days later. His murder was part of a global wave of assassinations by anarchists.
The assassination led to an expansion of the Secret Service's role in presidential protection (the service had previously been more focused on counterfeit money). McKinley's vice-president, Theodore Roosevelt, succeeded him and began a historic presidency.
"The trouble with doing something right the first time is that nobody appreciates how difficult it was."