While shaking hands at the Pan-American Exposition, William McKinley met with the anarchist Leon Czolgosz, who slapped his extended hand aside. The would-be assassin raised his hand wrapped in a handkerchief like a bandage and fired two shots from a hidden revolver. McKinley, reeling from the impertinence of slapping aside the president's hand, took a half-step sideways. One bullet grazed his ribs while the other cut a thin line across his torso but did little more than pierce the skin.
The rest of McKinley's presidency was hardly as exciting, and his vice-president Theodore Roosevelt continued the Republican Progressive Era with his election in 1904. During his two terms (1905-13) he would be responsible for actions such as the expedition of the Great White Fleet, the construction of the Panama Canal in northern Columbia (the rights for which McKinley's administration had paid Columbia $25,000,000), negotiating the end to the Russo-Japanese War, and breaking up many of the US's overbearing monopolies. In 1912, the Republicans would continue in the White House with Roosevelt's vice-president Taft winning the election against New Jersey Governor Woodrow Wilson.
With war in Europe in 1914, Roosevelt would return from his safari in Africa and press America to take part. Taft would disagree publicly, and the country would be divided between them. Many Republicans wanted nothing to do with a European war while those with Roosevelt were ready to charge into the fray like a “Bull Moose.” With the Republicans crippling themselves, Wilson would take to the campaign trail. By 1916, however, the Republican committee solved its division with Charles Hughes taking the presidency, Taft being prepared for the Supreme Court, and Roosevelt readying a potential expedition if the war did come to America.
In 1917, the war did come with the Zimmerman Telegram to Mexico. Roosevelt led the American Expeditionary Forces aided by General John J. Pershing. By the war's end, Roosevelt's opinion of the honors and glories of wars would change, and he would retire from politics permanently. Americans would take up a similar opinion and leave Europe to itself, which created an especially crippling Treaty of Versailles for the Central Powers. With a sense of blame for the war, the Republican Progressive Era would come to an end with Democrat James Cox coming to the White House in 1920 with his VP Franklin Roosevelt, a distant cousin of Theodore.
Their campaign had been a “Return to Normalcy,” though the following decade would be one of unprecedented economic and social growth. With the fall in 1929 and the Great Depression, the Democrats would find blame of their own despite then-president FDR's Works Progress Administration. Voters would turn back to Republicans with Herbert Hoover and his many alleviation projects, but his “do it yourself” ideals backfired as people looked to improve life in America through unity and strength, just as the nations of Italy and Germany had done in becoming fascist.
In reality, William McKinley was killed by the assassin Czolgosz. The second bullet pierced McKinley's stomach, kidney, and pancreas. With limited surgical facilities at the exposition, doctors were unable to remove the bullet. The president would die of gangrene in the early hours of September 14, 1901. Czolgosz was executed by electric chair October 29.