Almost twenty years to the day of the death of President James Garfield, tragedy would again strike and questions of presidential disability and succession raised when Leon Czolgosz shot another chief executive hailing from Ohio, William McKinley, on September 6, 1901 in Buffalo, New York.  Like Garfield, McKinley would not die immediately, lingering for eight days and slipping in and out of a coma before dying on September 14.

Roosevelt for his part came to Buffalo immediately upon hearing of the shooting, but while members of McKinley's cabinet and of Congress both in some cases made pleas for Roosevelt to become Acting President, he demurred, in part out of respect for McKinley and in part because he suspected doing so would open a Pandora's Box - despite two prior assassinations and a reform of presidential succession law, there was still no apparatus in place defining what made a President incapacitated, who would declare him to be incapacitated, or under what circumstances a recovered President would return to work.

As for the President, McKinley likely would have given his blessing to Roosevelt serving as Acting President... had anyone bothered to ask him.