Gun violence in the United States been made on U.S. presidents (over one-fifth of all presidents); four were successful, three with handguns and one with a rifle. Abraham Lincoln survived an earlier attack, but was killed using a .44-caliber Derringer pistol fired by John Wilkes Booth. James A. Garfield was shot two times and mortally wounded by Charles J. Guiteau using a .44-caliber revolver on July 2, 1881. He would die of pneumonia the same year on September 19. On September 6, 1901, William McKinley was fatally wounded by Leon Czolgosz when he fired twice at point-blank range using a .32-caliber revolver. Despite only being struck
Charles J. Guiteau storage by the museum. Parts of Guiteau's brain remain on display in a jar at the Mütter Museum in Philadelphia. Dr. Allan McLane Hamilton said in 1881 that he believed that Guiteau was sane when he assassinated Garfield. An autopsy of Guiteau's brain revealed that his dura mater was abnormally thick, suggesting he may have had neurosyphillis, a disease which causes mental instability; he could have contracted the disease from a prostitute. George Paulson, formerly the chair of neurology at Ohio State University, disputed the neurosyphillis diagnosis, arguing that Guiteau suffered from both schizophrenia and "grandiose narcissism". In 2014, the